Kolaviron abates busulfan-induced episodic memory deficit and testicular dysfunction in rats: The implications for neuroendopathobiological changes during chemotherapy.

Busulfan is a popular antileukemia chemotherapeutic alkylating agent widely known to induce variety of serious adverse effects including chemobrain-related cognitive impairments and dysfunction in male reproductive system. Whether kolaviron, a neuro- and repro-active compound obtained from Garcinia kola, with neuroprotective and reproductive-promoting activities, mitigates busulfan-induced cognitive and male reproductive impairments remain unknown. Hence, we investigated the reversal effects of kolaviron on busulfan-induced episodic memory deficit and testicular dysfunction, and its underlying mechanisms in male rats. In the treatment-protocol, rats in groups 1 and 2 received saline (10 mL/kg/p.o./day) and DMSO (10 mL/kg/p.o./day) respectively, group 3 was given kolaviron (200 mg/kg/p.o./day), group 4 received busulfan (50 mg/kg/p.o./day) and group 5 was pretreated with busulfan (50 mg/kg/p.o./day) consecutively for 56 days prior to kolaviron treatment (200 mg/kg/p.o./day) from days 29-56. Episodic memory deficit was assessed using passive avoidance task (PAT). Following euthanization, blood samples, epididymal sperm, testes and brain were harvested and hormonal and neurochemical contents and their metabolizing enzymes were assayed. Kolaviron reversed busulfan-induced episodic cognitive deficit in the PAT. The reduced serotonin, dopamine, noradrenaline concentrations, elevated glutamate levels, acetylcholinesterase, monoamine oxidase-A and B activities were normalized by kolaviron. Kolaviron also reversed the busulfan-induced decreased testicular/body weights and spermatogenesis. Kolaviron abated busulfan-induced changes in androgenic hormones (testosterone, FSH, LH), dehydrogenase enzymes (3ß-HSD and 17ß-HSD), altered sperm-chromatin, sperm-membrane integrity and sperm-acrosomal reaction and capacitation impairments. Our findings suggest that kolaviron could mitigate busulfan-induced episodic memory deficit and dysfunction in male reproductive system via neurochemical modulations and increase testicular androgenic hormones/enzymes in rats.

Antioxidative, antimitotic, and DNA-damaging activities of Garcinia kola stem bark, Uvaria chamae root, and Olax subscorpioidea root used in the ethnotherapy of cancers.

Garcinia kola (GK) stem bark, Uvaria chamae (UC) root, and Olax subscorpioidea (OS) root are components of various indigenous/traditional anticancer regimens. It is, therefore, possible that they might combat oxidative stress and impair cellular proliferation linked to carcinogenesis. In this study, we investigated the antioxidative, mito-depressive, and DNA-damaging activities of the three plant extracts in order to provide further mechanistic insights into their potential anticancer roles in documented cancer remedies that include them. Antioxidative properties were investigated in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging assays and an animal model of drug (cisplatin)-induced oxidative stress. The Allium cepa assay and the single cell gel electrophoresis (SCGE) assay were used to assess mito-depressive and DNA-damaging activities. GK and OS showed significantly higher antioxidant activities in the DPPH assay than ascorbic acid; OS had the lowest IC50 of the three plants in the NO assay, comparable to that of ascorbic acid. Pretreatment with the extracts produced an ameliorative and protective effect against the cisplatin-induced oxidative stress as shown by inhibition of lipid peroxidation and improved or restored reduced glutathione and superoxide dismutase levels. In the Allium test, the three extracts produced significant decreases in root growth and also significant cytotoxicity as evidenced by decreased mitotic index. Each of the extracts also showed significantly increased tail DNA (%) in the SCGE assay, indicating the significant DNA-damaging effect. Taken together, this study demonstrates the possible chemopreventive and chemotherapeutic potentials of the three study extracts, which may explain the roles of their source plants in traditional remedies in the therapy of cancers.

The vitamin E derivative garcinoic acid from Garcinia kola nut seeds attenuates the inflammatory response.

The plant Garcinia kola is used in African ethno-medicine to treat various oxidation- and inflammation-related diseases but its bioactive compounds are not well characterized. Garcinoic acid (GA) is one of the few phytochemicals that have been isolated from Garcinia kola. We investigated the anti-inflammatory potential of the methanol extract of Garcinia kola seeds (NE) and purified GA, as a major phytochemical in these seeds, in lipopolysaccharide (LPS)-activated mouse RAW264.7 macrophages and its anti-atherosclerotic potential in high fat diet fed ApoE-/- mice. This study outlines an optimized procedure for the extraction and purification of GA from Garcinia kola seeds with an increased yield and a purity of >99%. We found that LPS-induced upregulation of iNos and Cox2 expression, and the formation of the respective signaling molecules nitric oxide and prostanoids, were significantly diminished by both the NE and GA. In addition, GA treatment in mice decreased intra-plaque inflammation by attenuating nitrotyrosinylation. Further, modulation of lymphocyte sub-populations in blood and spleen have been detected, showing immune regulative properties of GA. Our study provides molecular insights into the anti-inflammatory activities of Garcinia kola and reveals GA as promising natural lead for the development of multi-target drugs to treat inflammation-driven diseases.

Protective Effect of Kolaviron on Cyclophosphamide-Induced Cardiac Toxicity in Rats.

BACKGROUND: Cyclophosphamide (CP) is a nitrogen mustard alkylating drug used for the treatment of chronic and acute malignant lymphomas, myeloma, leukemia, neuroblastoma, adenocarcinoma, retinoblastoma, breast carcinoma, and immunosuppressive therapy. Despite its vast therapeutic uses, it is known to cause severe cardiac toxicity. Kolaviron (KV), a Garcinia kola seed extract containing a mixture of flavonoids, is reputed for its antioxidant and membrane stabilizing properties. OBJECTIVE: This study investigated the protective effect of KV on CP-induced cardiotoxicity in rats. METHODS: Thirty rats were used, and they were divided into 6 groups of 5 rats each. Group I received 2 mL/kg propylene glycol orally for 14 days; group II received CP (50 mg/kg/d, intraperitoneally [i.p.]) for 3 days; groups III and IV received 200 and 400 mg/kg/d KV, respectively, orally for 14 days and groups V and VI were pretreated with 200 and 400 mg/kg/d KV, respectively, orally for 14 days followed by CP (50 mg/kg/d, i.p.) for 3 days. RESULTS: CP treatment resulted in a significantly lower food consumption and body weight in rats. The lactate dehydrogenase and creatine kinase enzymes in cardiac tissues of rats treated with CP were significantly higher. In cardiac tissues, 3-day doses of CP resulted in significantly higher heart weight, cardiac troponin I, myeloperoxidase, malondialdehyde, hydrogen peroxide and lower superoxide dismutase, catalase, glutathione peroxidase activities, and reduced glutathione levels. Histological examination of cardiac tissues showed sign of necrosis of myocardium after CP treatment. However, administration of KV at 200 and 400 mg/kg for 14 days prior to CP treatment, increase food consumption, body weight, and attenuates the biochemical and histological changes induced by CP. CONCLUSIONS: These results revealed that KV attenuates CP-induced cardiotoxicity by inhibiting oxidative stress and preserving the activity of antioxidant enzymes.

Kolaviron and Garcinia kola Seed Extract Protect Against Ischaemia/Reperfusion Injury on Isolated Rat Heart.

BACKGROUND: The incidence of cardiovascular diseases and its associated complications have increased greatly in the past three decades. The purpose of this study was to evaluate the acute cardioprotective effects of Garcinia kola (GK) seed extract and Kolaviron (KV) and determine mechanisms of action involving RISK signalling pathways. METHODS: Male Wistar rats were used in this study. Hearts were excised and mounted on the Langendorff perfusion system. The control, group 1 was perfused with dimethyl sulfoxide (DMSO), group II with KV and group III with GK respectively. Western blot analyses were performed on frozen heart tissues. RESULTS: Isolated rat hearts perfused with KV and GK attenuated apoptotic pathways with significant reduction in p38 MAPK protein phosphorylation, as well as reduction in total caspase 3, cleaved caspase 3 (Asp 175) and PARP cleavage. KV and GK also down-regulated p-JNK1 (Tyr 185) and p-JNK 2 (Thr 183) protein expression at the 10 min reperfusion time ponit. Cardioprotection was achieved in part, by enhancement of the reperfusion injury signalling kinase (RISK) pathway; as evidenced by significant increases in protein expresion of Akt/PKB and p-Akt/PKB (Ser 473) in KV and GK respectively. CONCLUSIONS: KV and GK supplementation led to significant increases in the expressions of survival proteins. It is noteworthy that both KV and GK supplementation offered cardioprotection in ischaemic/reperfusion injury rat heart model. In all, GK showed better cardioprotective effect that KV.

Kolaviron and Garcinia kola attenuate doxorubicin-induced cardiotoxicity in Wistar rats.

Background The Garcinia kola seeds have been reported for its antibacterial, antioxidant, antidiabetic and also for its chemoprevention property. The use of doxorubicin as an anticancer drug has been accompanied with avalanche of side effects including cardiotoxicity. The aim of this study was to investigate the cardioprotective effect of Kolaviron and Garcinia kola and their mechanisms of action. Methods Sixty male rats (Wistar strain) were used in this study. They were divided into 6 groups (A-F) each containing 10 animals. Group A was the control. Rats in Groups B, C, D, E and F were treated with doxorubicin at the dosage of 15 mg/kg body weight i.p. Prior to this treatment, rats in groups C, D, E and F were pre-treated orally with Kolaviron at the dosage of 100 mg/kg and 200 mg/kg, and Garcinia kola 100 mg/kg and 200 mg/kg for 7 days, respectively. Results The results show that doxorubicin caused a significant increase in heart rate and prolonged QT, reduced antioxidant status, increased oxidative stress, inflammation and markers of cardiac damage which were reversed by pre-treatment with Kolaviron and Garcinia kola. Conclusions Overall, pre-treatment with Kolaviron or Garcinia kola caused reversal of cardiac damage, ECG alteration and oxidative stress by increasing the activity of antioxidant enzymes and reducing the markers of inflammation on doxorubicin-induced cardiotoxicity.

Garcinia kola aqueous suspension prevents cerebellar neurodegeneration in long-term diabetic rat - a type 1 diabetes mellitus model.

ETHNOPHARMACOLOGICAL RELEVANCE: The development of compounds able to improve metabolic syndrome and mitigate complications caused by inappropriate glycemic control in type 1 diabetes mellitus is challenging. The medicinal plant with established hypoglycemic properties Garcinia kola Heckel might have the potential to mitigate diabetes mellitus metabolic syndrome and complications. AIM OF THE STUDY: We have investigated the neuroprotective properties of a suspension of G. kola seeds in long-term type 1 diabetes mellitus rat model. MATERIALS AND METHODS: Wistar rats, made diabetic by single injection of streptozotocin were monitored for 8 months. Then, they were administered with distilled water or G. kola oral aqueous suspension daily for 30 days. Body weight and glycemia were determined before and after treatment. After sacrifice, cerebella were dissected out and processed for stereological quantification of Purkinje cells. Histopathological and immunohistochemical analyses of markers of neuroinflammation and neurodegeneration were performed. RESULTS: Purkinje cell counts were significantly increased, and histopathological signs of apoptosis and neuroinflammation decreased, in diabetic animals treated with G. kola compared to diabetic rats given distilled water. Glycemia was also markedly improved and body weight restored to non-diabetic control values, following G. kola treatment. CONCLUSIONS: These results suggest that G. kola treatment improved the general condition of long-term diabetic rats and protected Purkinje cells partly by improving the systemic glycemia and mitigating neuroinflammation.

Three indigenous plants used in anti-cancer remedies, Garcinia kola Heckel (stem bark), Uvaria chamae P. Beauv. (root) and Olax subscorpioidea Oliv. (root) show analgesic and anti-inflammatory activities in animal models.

ETHNOPHARMACOLOGICAL RELEVANCE: Phytochemicals with anti-oxidative and anti-inflammatory properties are known to inhibit tumour initiation, promotion and progression. Hence, there is an increasingly-convincing rationale for employing remedies containing those phytochemicals in the treatment of cancers and also as analgesic and anti-inflammatory adjuvants in therapy. The plants Garcinia kola Heckel (Clusiaceae), stem bark; Uvaria chamae P. Beauv. (Annonaceae), root; and Olax subscorpioidea Oliv. (Olacaceae), root, have been documented to be part of various indigenous anti-cancer regimens. AIM OF THE STUDY: To determine if the three plants exhibit significant anti-oxidative and anti-inflammatory properties. MATERIALS AND METHODS: Using established models, the analgesic and anti-inflammatory activities of the three plants were investigated. RESULTS: Pre-treatment with the plant extracts at 100, 200 and 400mg/kg produced inhibition of writhes; G. kola and U. chamae showed no significant effect on formalin-induced pain, but O. subscorpioidea produced inhibition in both phases of the formalin test. Similarly, while G. kola and U. chamae did not produce any significant inhibitory effect in the xylene-induced ear oedema model, the oedema was significantly reduced by O. subscorpioidea pre-treatment. However, all the three plants significantly inhibited the time-dependent increase in paw circumference in the carrageenan- and formaldehyde-induced rat paw oedema tests, with peak effects observed at 400mg/kg, 6h after the induction of oedema, comparable in some cases to the effects of two standard drugs, the non-steroidal anti-inflammatory drug diclofenac and the anti-inflammatory antibiotic doxycycline. CONCLUSION: We conclude that the three plant extracts possess analgesic and anti-inflammatory properties, thus providing a scientific rationale for their inclusion in some traditional anti-cancer regimens.

Ameliorative Effects of Kolaviron, a Biflavonoid Fraction from Garcinia Kola Seed, on Hepato-renal Toxicity of Anti-tuberculosis Drugs in Wistar Rats.

BACKGROUND: Tuberculosis (TB) is an infectious disease of international health priority. The combination of anti-TB drugs (4-Tabs)- isoniazid (INH), rifampicin (RIF), pyrazinamide (PZA) and ethambutol (ETB) are effective in the management of the disease, however, their toxic effect is a major concern. PURPOSE: The study was designed to evaluate the toxicity of anti-TB drugs in male Wistar rats and possible ameliorative effects of kolaviron (KV), a biflavonoid from Garcinia kola seeds. METHODS: Twenty-eight rats were assigned into four groups; Group 1 (Control) received corn oil, Group 2 (4-Tabs) received therapeutic doses of INH (5 mg/kg), RIF (10 mg/kg), PZA (15 mg/kg) and ETB (15 mg/kg) in combination, Group 3 (4-Tabs + KV) received INH, RIF, PZA, ETB and KV (200 mg/kg) and Group 4 (KV) received KV (200 mg/kg) by oral gavage three times per week for 8 consecutive weeks. RESULTS: Administration of 4-Tabs caused oxidative stress resulting in significant (p = 0.031, 0.027) increase in malondialdehyde levels in the liver and kidney of rats by 101% and 34%, respectively. Also, 4-Tabs caused significant (p = 0.023-0.035) elevation of serum alanine and aspartate aminotransferases by 41% and 48%, creatinine by 252% and total bilirubin by 89%, respectively. In contrast, hepatic and renal antioxidant indices- reduced glutathione, glutathione peroxidase, glutathione-s-transferase and superoxide dismutase were significantly (p = 0.028-0.039) decreased in 4-Tabs-treated rats. Co-administration of KV with 4-Tabs significantly restored the antioxidant parameters and biochemical indices to near normal. CONCLUSION: These findings suggest that anti-TB drugs elicit oxidative damage in liver and kidney of rats while KV protects against the adverse effects via antioxidative mechanism.

Biflavonoid fraction from Garcinia kola seed ameliorates hormonal imbalance and testicular oxidative damage by anti-tuberculosis drugs in Wistar rats.

BACKGROUND: Tuberculosis (TB) is a global health problem. The effects of anti-TB drugs on male reproductive system have not been properly evaluated. We investigated the effects of anti-TB drugs on testicular antioxidant indices, sperm characteristics and hormonal levels in rats, and the protective role of kolaviron (KV), a biflavonoid from Garcinia kola seed. METHODS: Twenty-eight male Wistar rats were assigned into four groups and orally treated with corn oil (control), anti-TB drugs [4-Tabs=isoniazid (5 mg/kg), rifampicin (10 mg/kg), pyrazinamide (15 mg/kg) and ethambutol (15 mg/kg) in combination], anti-TB drugs +KV and KV alone (200 mg/kg). Anti-TB drugs and KV were given three times per week for 8 weeks. In vitro, reducing power, inhibition of lipid peroxidation (LPO), diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging effects of KV were examined. RESULTS: KV at 10, 20, 50 and 100 µg/mL showed strong reducing potential and effectively scavenged DPPH and OH radicals in a concentration-dependent manner. Furthermore, KV significantly inhibited LPO in rats' liver homogenate. In vivo, administration of 4-Tabs caused a significant (p<0.05) decrease in body weight gain and weight of testis of rats. Body weight gain and weight of testis decreased by 45% and 36%, respectively, in the 4-Tabs-treated rats. Also, 4-Tabs increased testicular lipid peroxidation by 82%, with a concomitant decrease in antioxidant indices. Testicular reduced glutathione, superoxide dismutase and glutathione peroxidase decreased by 2.2-, 1.9- and 1.6-folds, respectively. Likewise, 4-Tabs markedly decreased sperm count, motility, luteinizing hormone and testosterone. Co-administration of KV with 4-Tabs normalized body weight, enhanced antioxidant system and improved sperm characteristics. CONCLUSIONS: Kolaviron protects male reproductive system from oxidative damage by anti-tuberculosis drugs via the antioxidative mechanism.

Comparison of antioxidant effects of kolaviron and vitamin C interventions on testicular structures following nevirapine administration in Sprague-Dawley rats / Comparación de los efectos antioxidantes en la intervención con kolaviron y vitamina C sobre las estructuras testiculares después de la administración de nevirapina en ratas Sprague-Dawley

Testicular toxicity has been implicated in highly active anti-retroviral therapy (HAART) treatment. Hence there is need to identify an effective antioxidant product that can alleviate testicular necrosis due to HAART administration. Forty eight adult male Sprague-Dawley rats were used in this study. The animals were divided into eight (8) groups: A-H (n= 6). Group A animals received normal saline as the control; Group B was given Nevirapine (Nv); Group C was given Kolaviron (Kv); Group D was given vitamin C; Group E was given Nv and Kv; Group F was given Nv and Vitamin C; Group G was given Nv for 56 d and Kv for 28 d serving as a withdrawal group; Group H was given corn oil. Nv, Kv and Vit. C were given at 1.54, 200 and 250 (mg·kg)/bw respectively while all administrations were through oral gavage. The body weights were taken every other day. Thereafter, they were anaesthetized with halothane. The testes were excised, weighed, fixed in Bouin's fluid and stained with H&E while the epididymes removed for semen fluid analyses. The results showed a significant (P<0.05) decrease in sperm motility in group E (Nevirapine + kolaviron) when compared with group F (Nevirapine + Vitamin C) while Sperm count was not significantly different (P>0.05) across the groups. The testicular histoarchitectural studies revealed indistinct spermatogonia, necrotic interstititial endocrine cells in the altered interstitial space, fragmented spermatids, atrophy of mature spermatocytes, degenerated germ cells, obliterated seminiferous tubules lumen, undifferentiated spermatogonia and cellular debris in the somniferous tubules lumen of nevirapine administered group but normal across the other groups. In the testis, there were no significant reduction in SOD, Catalase and GPx activities but a significant decrease in GST activity (P<0.001) when group E was compared with group F. In conclusion, vitamin C presents a better remediation in nevirapine induced spermiotoxicity compared to kolaviron in Sprague-Dawley rats.

La toxicidad testicular ha sido implicada en la terapia antirretroviral altamente activa (TARAA). Por lo tanto existe la necesidad de identificar un producto antioxidante eficaz que pueda aliviar la necrosis testicular en la administración de la TARAA. Cuarenta y ocho ratas macho Sprague-Dawley adultas fueron utilizadas. Los animales se dividieron en ocho (8) grupos: AH (n= 6). Grupo A, animales recibieron solución salina normal como el control; Grupo B, recibió Nevirapina (Nv); Grupo C, recibió Kolaviron (Kv); Grupo D, recibió vitamina C; Grupo E, recibió Nv y Kv; Grupo F, recibió Nv y vitamina C; Grupo G, recibió Nv durante 56 d y Kv por 28 d como un grupo de retirada; Grupo H, recibió aceite de maíz. Nv, Kv y Vit. C se administraron en dosis de 1, 54, 200 y 250 (mg · kg) de peso corporal respectivamente; todas las administraciones fueron por sonda oral. Los pesos corporales se tomaron cada dos días. A partir de ese momento los animales fueron anestesiados con halotano. Los testículos fueron extirpados, pesados y fijados en solución de Bouin y teñidos con H&E, mientras que el epidídimo se retiró para analizar el semen. Los resultados mostraron un descenso (p<0,05) en la motilidad de los espermatozoides en el grupo E (Nevirapina + Kolaviron) en comparación con el grupo F (Nevirapina + vitamina C), mientras que el recuento espermático no mostró diferencias significativas (P>0,05) entre los grupos. El estudio de la histoarquitectura testicular reveló espermatogonias indiferenciadas, con células intersticiales necróticas en el espacio intersticial y espermátidas fragmentadas. Además, en el grupo que recibió Nevirapina mostró espermatocitos maduros atrofiados, degeneración de células germinales, lumen de los túbulos seminíferos obliterados, espermatogonias indiferenciadas y restos celulares en el lumen de los tubulos seminíferos. En el resto de los grupos los resultados fueron normales. En el testículo hubo una reducción significativa en las actividades de la superóxido dismutasa, catalasa y glutatión peroxidasa, pero una disminución significativa en la actividad glutatión S-transferasa (P <0,001) al comparar los grupo E y F.

Effects of kolaviron on hepatic oxidative stress in streptozotocin induced diabetes.

BACKGROUND: Alteration in antioxidant defence and increase in oxidative stress that results in tissue injury is characteristic of diabetes. We evaluated the protective effects of kolaviron (a flavonoid complex extracted from the seeds of Garcinia kola) on hepatic antioxidants, lipid peroxidation and apoptosis in diabetic rats. METHODS: To induce diabetes, rats were injected with streptozotocin intraperitoneally at a single dose of 50 mg/kg. Kolaviron (100 mg/kg) was administered orally for 6 weeks (5 times weekly). Activities of liver antioxidant enzymes was analysed with Multiskan Spectrum plate reader. High performance liquid chromatography (HPLC) was used in the analysis of MDA (malondialdehyde), a product of lipid peroxidation. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULT: Diabetic rats exhibited a significant increase in the peroxidation of hepatic lipids as observed from the elevated level of malondialdehyde (MDA). In addition, Oxygen Radical Absorbance Capacity (ORAC), level of reduced glutathione (GSH), ratio of reduced to oxidized glutathione (GSH: GSSG) and catalase (CAT) activity were decreased in the liver of diabetic rats. The activities of GPX (glutathione peroxidase) and SOD (superoxide dismutase) were unaltered in diabetic rats. TUNEL assay revealed increased apoptotic cell death in the liver. Kolaviron attenuated lipid peroxidation and apoptosis, increased CAT activity, GSH levels and GSH: GSSG ratio. The ORAC of kolaviron-treated diabetic liver was restored to near-normal values. CONCLUSION: Kolaviron protects the liver against oxidative and apoptotic damage induced by hyperglycemia.

Protective activity of biflavanones from Garcinia kola against Plasmodium infection.

ETHNOPHARMACOLOGICAL RELEVANCE: Garcinia kola is a medicinal plant traditionally used for malaria therapy in Central Africa. AIM OF THE STUDY: To evaluate the antimalarial potencies in vitro and in vivo of pure biflavanones from G. kola. MATERIALS AND METHODS: The pure biflavanones were obtained by bioassay-guided fractionation of a 70% ethanol extract of G. kola seeds and their chemical structures were elucidated by comparison of their NMR ((1)H and (13)C) and mass spectral data with those provided in the literature. Plasmodium falciparum (FCR-3, cycloguanil-resistant strain from Gambia) was used for in vitro assessments of antimalarial activities. Growth inhibition, intraerythrocytic development and parasite morphology were evaluated in culture by the microscopic observation of Giemsa-stained thin blood films. The cytotoxicity of the antimalarial compounds was evaluated against KB 3-1 (human epidermoid carcinoma) cells by MTT assay. In vivo antimalarial activities were determined in mice infected with Plasmodium berghei (ANKA strain) following a four-day suppressive test. RESULTS: The bioassay-guided fractionation of an extract of G. kola resulted in the isolation of three biflavanones (GB-1a, GB-1, and GB-2) as its active principles. These three biflavanones displayed not only potent inhibitory activity in vitro against P. falciparum proliferation but also antimalarial potency through oral administration in mice infected with P. berghei without signs of acute toxicity. GB-1 was found to exhibit the strongest in vitro antimalarial potency on P. falciparum with an IC50 of 0.16µM, whereas it exhibited a very low in vitro cytotoxicity on KB 3-1 cells with an IC50 of greater than 150µM. During an in vivo antimalarial assay in mice infected with P. berghei, GB-1 was found to exhibit biological potency with an approximate ED50 of 100mg/kg following oral administration. GB-1 was also shown to increase the average life span of the infected mice significantly compared to that of control mice (p<0.01 Student's t-test). CONCLUSIONS: The antimalarial outcome of GB-1a, GB-1, and GB-2 may be related to the traditional utilization of this crude drug against malaria judging from their significant content in G. kola nuts. GB-1 showed the most potent antimalarial activity with a high selectivity index and, therefore could be exploited to identify the molecular target, which subsequently could be helpful to design novel therapeutics against malaria. GB-1 may be considered a promising antimalarial candidate for trial in vivo using higher animals infected with P. falciparum.

Modulatory role of kolaviron in phenytoin-induced hepatic and testicular dysfunctions in Wistar rats.

Phenytoin, an anticonvulsant agent used for the treatment of epilepsy has been reported to exhibit toxic side effects on the liver and testes. The present study investigated the protective effects of kolaviron (KV, a bioflavonoid from Garcinia kola seeds) against hepatic and testicular damage in rats exposed to phenytoin. The study consisted of four groups of six rats per group. Group I rats received 2 mL/kg of corn alone while group II received 75 mg/kg of phenytoin (PHT) alone. Groups III and IV were co-treated with kolaviron (200 mg/kg KV) and vitamin E (500 mg/kg VTE), respectively, for 14 days. The antioxidant status, hepatic and reproductive functional parameters were subsequently determined. PHT treatment significantly (p < 0.05) increased superoxide dismutase (SOD) and catalase (CAT) activities, elevated lipid peroxidation (LPO) and hydrogen peroxide (H2O2) levels along with significant reduction in the hepatic and testicular levels of glutathione (GSH). Moreover, PHT exposure elicited significant increases in alkaline phosphatase (ALP) and aspartate aminotransferase (AST) levels. The significant reduction in seminal epithelium thickness and the diameter of seminiferous tubules was accompanied with marked decrease in sperm motility, sperm count, and viability in PHT-treated rats. However, antioxidant status and the functional indices of liver and testes were restored to near control levels in rats co-treated with KV and VTE. In conclusion, KV and VTE protect the liver and testes against functional impairment due to PHT treatment.

Kolaviron, a biflavonoid complex of Garcinia kola seeds modulates apoptosis by suppressing oxidative stress and inflammation in diabetes-induced nephrotoxic rats.

Diabetic nephropathy is a complex disease that involves increased production of free radicals which is a strong stimulus for the release of pro-inflammatory factors. We evaluated the renal protective effect of kolaviron (KV) - a Garcinia kola seed extract containing a mixture of 5 flavonoids, in diabetes-induced nephrotoxic rats. Male Wistar rats were divided into 4 groups: untreated controls (C); normal rats treated with kolaviron (C+KV); untreated diabetic rats (D); kolaviron treated diabetic rats (D+KV). A single intraperitoneal injection of streptozotocin (STZ, 50mg/kg) was used for the induction of diabetes. Renal function parameters were estimated in a clinical chemistry analyzer. Markers of oxidative stress in the kidney homogenate were analyzed in a Multiskan Spectrum plate reader and Bio-plex Promagnetic bead-based assays was used for the analysis of inflammatory markers. The effect of kolaviron on diabetes-induced apoptosis was assessed by TUNEL assay. In the diabetic rats, alterations in antioxidant defenses such as an increase in lipid peroxidation, glutathione peroxidase (GPX) activity and a decrease in catalase (CAT) activity, glutathione (GSH) levels and oxygen radical absorbance capacity (ORAC) were observed. There was no difference in superoxide dismutase (SOD) activity. Diabetes induction increased apoptotic cell death and the levels of interleukin (IL)-1ß and tumor necrosis factor (TNF)-α with no effect on IL-10. Kolaviron treatment of diabetic rats restored the activities of antioxidant enzymes, reduced lipid peroxidation and increased ORAC and GSH concentration in renal tissues. Kolaviron treatment of diabetic rats also suppressed renal IL-1ß. The beneficial effects of kolaviron on diabetes-induced kidney injury may be due to its inhibitory action on oxidative stress, IL-1ß production and apoptosis.

Kolaviron, a natural flavonoid from the seeds of Garcinia kola, reduces LPS-induced inflammation in macrophages by combined inhibition of IL-6 secretion, and inflammatory transcription factors, ERK1/2, NF-κB, p38, Akt, p-c-JUN and JNK.

BACKGROUND: Kolaviron (Kol-v), an important component of Garcinia kola seed has a variety of biologic activities, including anti-inflammatory properties. METHODS: We tested the ability of Kol-v to block signalling pathways implicated in lipopolysaccharide (LPS)-induced inflammatory gene expression in RAW 264.7 macrophage cell line. RESULTS: When macrophages pre-treated with Kol-v (15 and 25µM) were activated with LPS, phosphorylation of p38 and p-c-JUN but not IκBα degradation and phosphorylation of NF-κB (p65), ERK1/2, and IκBα were blocked. Furthermore, Kol-v suppressed LPS-induced increase in the expression of IL-18 gene and LPS-induced decrease in the mRNA expression of IP-10 but it had no effect on the LPS-induced decrease in the gene expression levels of IL-1α, IL-33, IL-1ß, and IFNß1-1. When macrophages pre-treated with Kol-v (50 and 100µM) were activated with LPS, phosphorylation of Akt, ERK1/2, IκBα, and NFκB (p65) but not that of CREB was blocked by Kol-v. The protective effect of Kol-v on the LPS-induced phosphorylation of the mitogen activated protein kinase (MAPK) family member JNK was only observed at 100µM. At all concentrations of Kol-v (0-100µM) tested in this study, there was no effect of Kol-v on LPS-induced secretion of the pro-inflammatory cytokine TNF-α but a concentration dependent inhibition of Kol-v on IL-6 secretion was observed. CONCLUSION: Kol-v interferes with LPS signalling by reducing the activation of several inflammatory transcription factors and that its inhibitory action on IL-6 secretion correlates with inhibition of ERK1/2, p38, Akt, p-c-JUN and JNK signalling pathways. GENERAL SIGNIFICANCE: The anti-inflammatory potential of Kol-v via inhibition of IL-6 secretion in RAW macrophage was established in this study.

Gas chromatography-mass spectrometry characterisation of the anti-Listeria components of Garcinia kola seeds.

Adsorption chromatography was used to separate the bioactive constituents of the crude n-hexane extract of Garcinia kola seeds. The silica gel 60 column fractions were eluted using the solvent combination of benzene: ethanol : ammonium hydroxide (BEA) in the ratio combination of 36 : 4 : 0.4 v/v. The fractions were tested for anti-Listeria activities by determining their MIC50, MIC90 or MIC against 4 Listeria isolates. The fractions were labelled BEA1 to BEA5 and 3 out of the 5 fractions eluted were active against the test Listeria species with MIC's ranging from MIC 0.57 mg/mL to MIC50 0.625 mg/mL. The most active fractions, BEA2 and BEA3, were subjected to gas chromatography coupled to mass spectrometry (GC-MS) to identify their composition. Fraction BEA2 constituted of 18 compounds mostly sterols and the BEA3 fraction contained 27 compounds with the most abundant compounds being fatty acids derivatives. The BEA2 fraction's interactions with antibiotics proved to be 100% synergistic with ciprofloxacin and ampicillin whilst it exhibited 50% additivity and 50% synergism with penicillin G. However, all the interactions of the BEA2 fraction with each of the conventional antibiotics used were synergistic against the human listeriosis causative bacteria Listeria monocytogenes.

Kolaviron, a Garcinia biflavonoid complex ameliorates hyperglycemia-mediated hepatic injury in rats via suppression of inflammatory responses.

BACKGROUND: Chronic inflammation plays a crucial role in hyperglycemia-induced liver injury. Kolaviron (KV), a natural biflavonoid from Garcinia kola seeds have been shown to possess anti- inflammatory properties which has not been explored in diabetes. To our knowledge, this is the first study to investigate the effect of KV on pro-inflammatory proteins in the liver of diabetic rats. METHODS: Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ) (50 mg/kg) in male Wistar rats. Kolaviron (100 mg/kg) was administered orally five times a week for six weeks. The concentrations of cytokines and chemokine were measured using Bio-plex Pro™ magnetic bead-based assays (Bio-Rad Laboratories, Hercules, USA). Plasma glucose and serum biomarkers of liver dysfunction were analyzed with diagnostic kits in an automated clinical chemistry analyzer. Insulin concentration was estimated by radioimmunoassay (RIA). RESULT: Kolaviron (100mg/kg) treatment significantly ameliorated hyperglycemia and liver dysfunction. Serum levels of hepatic marker enzymes were significantly reduced in kolaviron treated diabetic rats. Kolaviron prevented diabetes induced increase in the hepatic levels of proinflammatory cytokines; interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF-α) and monocyte chemotactic protein (MCP-1). CONCLUSION: The results of this study demonstrate that the hepatoprotective effects of kolaviron in diabetic rats may be partly associated with its modulating effect on inflammatory responses.

Kolaviron prevents ethylene glycol monoethyl ether-induced testicular apoptosis via down-regulation of stress proteins, Fas/Fas-L and caspases expressions in rats.

This study investigated the protective role of kolaviron, a natural antioxidant biflavonoid isolated from the seed of Garcinia kola, in ethylene glycol monoethyl ether (EGEE)-induced testicular dysfunction in male rats. Adult male Wistar rats were exposed to EGEE (200 mg/kg) separately or in combination with either kolaviron (100 or 200 mg/kg) or vitamin E (50 mg/kg) for 14 days. Immunoblot analysis revealed that EGEE exposure alone significantly increased stress-inducible proteins levels. The increased protein expression of active caspases, Fas and Fas-L, was accompanied by nuclear factor kappa B downregulation and elevation of cytosolic cytochrome c level in EGEE-treated rats. In addition, the observation from immunofluorescence staining was consistent with the increased TUNEL-positive nuclei in the testes of EGEE-treated rats. Kolaviron and vitamin E significantly inhibited induction of stress proteins and germ cell apoptosis in EGEE-treated rats. Overall, kolaviron by virtue of its antioxidant and anti-apoptotic properties prevented EGEE-induced reproductive toxicity in rats.

Some bioactive potentials of two biflavanols isolated from Garcinia kola on cadmium-induced alterations of raw U937 cells and U937-derived macrophages.

OBJECTIVE: To investigate the abilities of two flavonoids - Garcinia biflavanol-1 (GB-1) and Garcinia biflavanol-2 (GB-2) from Garcinia kola (G. kola) in reducing cadmium-induced effects on raw U937 cells and U937-derived macrophages. METHODS: Macrophage U937 cells were incubated with cadmium followed by treatment with the flavonoids and cell viability assessed via trypan blue staining. In the other experiment, the U937 cells were transformed to the macrophage form and treated with cadmium in order to activate them. The cells were later incubated with the flavonoids and finally the supernatant of each cell culture was analysed for the secretion of nitric oxide, catalyse activity, and the release of tumour necrosis factor-alpha, interleukin-1 and interleukin-2 as indices of macrophage activation. Quercetin (a flavonol) was used as the reference flavonoid in all experiments. RESULTS: It revealed that the flavonoids significantly increased the viability of the cells and also reduced the cadmium-induced activation of the macrophage cells in a concentration-dependent manner. The flavanols GB-1 and GB-2 possessed higher activities than quercetin in all cases (P<0.05). Garcinia biflavanol-2 possessed a higher bioactivity than GB-1 significantly (P<0.05). CONCLUSIONS: In addition to corroborating the several reported importance of G. kola as a potential neutraceutical and pharmacological condiment, the study also clearly indicates the role hydroxylation especially at the 3'- position of polyphenols could play in enhancing bioactivities of flavonoids.