Chemical Composition, Antioxidant Potential, and Blood Glucose Lowering Effect of Aqueous Extract and Essential Oil of Thymus Serrulatus Hochst. Ex Benth.

Thymus serrulatus, an endemic plant of Ethiopia, is traditionally used to cure various diseases and as a food ingredient. In the Ethiopian folk medicine, the decoction is orally taken as a remedy to treat diabetes and high blood pressure. The purpose of the present study was to evaluate the antioxidant and antihyperglycemic effects of the aqueous extract and of the essential oil of Thymus serrulatus. The chemical composition of the aqueous extract was determined by LC-MS and the essential oil was characterized by GC-MS analysis. Radical scavenging assays, namely scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH•), hydroxyl (•OH), and nitric oxide (•NO), were used as a first approach to screen the potential antioxidant abilities of the samples. Alpha-amylase and α-glucosidase inhibitory studies were also employed to evaluate the in vitro antihyperglycemic potential of the plant. The in vivo blood glucose lowering effect of the extracts was assessed using hypoglycemic activity and the oral glucose tolerance test in normal and in streptozotocin induced diabetic mice. When compared to the aqueous extract, the essential oil showed superior radical scavenging activity, particularly for •NO, as well as greater inhibitory potency against α-amylase and α-glucosidase (IC50 = 0.01 mg/ml and 0.11 mg/ml, respectively). Both tested samples showed a statistically significant antihyperglycemic effect. The aqueous extract at 600 mg/kg exerted maximum antihyperglycemic activity (44.14%), followed by the essential oil (30.82%). Body weight and glucose tolerance parameters were also improved by the samples both in normal and diabetic mice. The findings of this study support the hypothesis that aqueous extract and essential oil of T. serrulatus are promising therapeutic agents.

Antihyperglycemic Activity of TLC Isolates from the Leaves of Aloe megalacantha Baker in Streptozotocin-Induced Diabetic Mice.

BACKGROUND: Diabetes mellitus (DM) is a group of metabolic disorders that are characterized by hyperglycemia which results from defects in insulin release or its efficient use by the human body. Although significant progress has been made to manage DM and related complications, it remains a major global health problem. To this end, the search for new antidiabetic drugs from traditionally claimed medicinal plants is important. Aloe megalacantha Baker is an endemic plant used traditionally to treat diabetes in Ethiopia. This study aimed to investigate antidiabetic activity of isolates from the leaf of A. megalacantha Baker in streptozotocin-induced diabetic mice. METHODS: The exudate of A. megalacantha was collected by cutting the leaves and scraping the yellow sap and then dried at room temperature. The dried exudate was subjected to repeated thin layer chromatographic (TLC) separations using a mixture of solvent system to isolate the major compounds identified on the TLC plate. A single dose of streptozotocin (50 mg/kg) was injected intraperitoneally to overnight fasted mice to induce diabetes. Antidiabetic activity of TLC isolates was assessed by in vivo methods including oral glucose tolerance test, antihyperglycemic and hypoglycemic activity tests. RESULTS: Three major isolates were obtained from the TLC analysis of the exudate of A. megalacantha. Exudate and TLC isolates were found to be non-toxic up to a dose of 2000 mg/kg. The TLC isolates (Ia and Ib) significantly (p<0.05) reduced blood glucose levels and also increased body weight change of the diabetic mice compared with control groups. CONCLUSION: The present study demonstrated the ability of the exudate of A. megalacantha and its TLC isolates to significantly decrease blood glucose levels and increase body weights in mice, thus strengthening the claim of its traditional use in DM-related disorders.

Evaluation of the Effect of Hydroethanolic Root Extract and Solvent Fractions of Cyphostemma adenocaule (Steud. ex A. Rich) Descoings ex Wild & Drummond on Cell-Mediated Immune Response and Blood Cell Count in Mice.

INTRODUCTION: Cyphostemma adenocaule (Steud. ex A. Rich) Descoings ex wild & Drummond (Vitaceae) has been used in traditional medicine for the management of various immunological and hematological disorders in different areas of Ethiopia and the rest of the world. In Ethiopia, the plant is used for the management of enlarged spleen, rabies virus, helminthic infection, snake bite, and various types of tumors. OBJECTIVE: To evaluate the effect of hydroethanolic root extract and solvent fractions of Cyphostemma adenocaule on cell-mediated immunity (delayed-type hypersensitivity), organ index (spleen and liver), and blood cell count in Swiss albino mice. MATERIALS AND METHODS: Acute oral toxicity test was conducted using nulliparous and nonpregnant Swiss albino mice following OECD 425 limit test method. Delayed-type hypersensitivity model was used to evaluate the effect on cell-mediated immunity. The experimental animals were divided into twelve groups which were sensitized and challenged with sheep red blood cells on day 0 and day 7, respectively. Levamisole 50 mg/kg was used as stimulant control, whereas cyclophosphamide 30 mg/kg was used as suppressant control. Hydroethanolic root extract (100 mg/kg, 200 mg/kg, and 400 mg/kg), aqueous fraction (100 mg/kg, 200 mg/kg, and 400 mg/kg), and n-butanol fraction (100 mg/kg, 200 mg/kg, and 400 mg/kg) were administered for seven days. The paw volume was measured using a digital plethysmometer before challenge and 24 hours after challenge. Blood was collected, and organs (spleen and liver) were isolated from each challenged mouse to determine blood cell count and organ index, respectively. RESULTS: No mortality and noticeable behavioral changes were observed among all mice receiving hydroethanolic root extract and solvent fractions at a dose of 2000 mg/kg. Hydroethanolic root extract and solvent fractions of Cyphostemma adenocaule showed enhancement of delayed-type hypersensitivity, organ index, and blood cell count. Hydroethanolic root extract at a dose of 400 mg/kg showed the highest and statistically significant stimulation of delayed-type hypersensitivity (0.123 ± 0.010) and blood cell count compared to the vehicle. CONCLUSION: Hydroethanolic root extract and solvent fractions of Cyphostemma adenocaule showed a stimulatory effect on cell-mediated immunity and hematopoiesis.

Multiple Pathway-Mediated Gut-Modulatory Effects of Maerua subcordata (Gilg) DeWolf.

BACKGROUND: Gastrointestinal disorders are often poorly managed, especially in developing countries, where there are limited resources and therapeutic options. Despite the rich diversity of medicinal plants that offer effective treatment options with fewer side effects, studies that provide scientific verification are lacking. Maerua subcordata (Gilg) DeWolf is among the plants claimed to have wide traditional medicine, use, including as a remedy against gastrointestinal problems. Therefore, this work aimed to evaluate the gut-modulatory effects of a crude leaf extract of M. subcordata (MSL.Cr), as well as its possible mechanism of action. METHODS: A castor oil (10 mL/kg)-induced diarrheal mouse model was used to evaluate the antidiarrheal effect of MSL.Cr, and the spasmodic/antispasmodic effect of the extract was assessed using isolated rabbit jejunum with and without addition of standard cholinergic agonists/antagonists to predict the possible mechanism of action. RESULTS: MSL.Cr exhibited 40% and 80% protection against castor oil-induced diarrhea in mice at doses of 500 and 1,000 mg/kg, respectively. In isolated rabbit jejunum, the extract increased spontaneous contractions at low doses (0.01-0.1 mg/mL), and was sensitive to atropine, whereas it showed complete inhibition at higher doses (0.3-1 mg/mL). It was shown that the relaxant effect was possibly mediated by the involvement of phosphodiesterase-enzyme inhibition and K+-channel activation. The extract potentiated the control concentration-response curve of carbachol, shifting it to the left, similarly to the control drug papaverine. The potassium-channel opening-like activity of MSL.Cr was possibly mediated by the involvement of aspecific K+-channels inhibition, since tetraethylammonium, anunselective antagonist of K+ channels, significantly reversed its inhibitory effect. CONCLUSION: This study showed that the M. subcordata leaf extract demonstrated gut-modulatory effects, possibly mediated by a combination of muscarinic-receptor stimulation, phosphodiesterase inhibition, and aspecific K+-channel activation.

Evaluation of bronchodialatory and antimicrobial activities of Otostegia fruticosa: A multi-mechanistic approach.

Otostegia fruticosa, a plant belonging to the family Lamiaceae, is endemic to Ethiopia. In Ethiopian traditional medicine, O. fruticosa has been used for the treatment of several respiratory-related disorders. The present study was designed to evaluate the bronchodilatory and antimicrobial activities of O. fruticosa leaves crude extract (Of.Cr). Ex-vivo experiments were conducted on guinea-pig trachea provided with physiological oxygenated buffer solution using emkaBath setup. The crude extract was analyzed by gas chromatography-mass spectrometry. Of.Cr, showed the presence of terpenes, fragrance components, saponins, and higher fatty acids. Of.Cr when tested on contracted tracheal chains with carbamylcholine (CCh, 1 µM) and high K+ (80 mM) produced relaxation by showing higher potency against CCh with incomplete inhibition of high K+. Dicyclomine, used as a positive control, also showed selectively higher potency to inhibit CCh when compared with its effect against K+. In the anticholinergic curves, Of.Cr at 1 mg/mL deflected CCh-induced concentration-response curves (CRCs) competitively to the right like dicyclomine (0.03 µM) and atropine whereas a higher dose of Of.Cr (3 mg/mL) produced a non-parallel shift in the CCh curves like a higher dose of dicyclomine (0.1 µM). In the calcium channel inhibitory assay, Of.Cr at 3 & 5 mg/mL, deflected CRCs of Ca++ to the right like verapamil, used as positive control. Of.Cr, at concentrations (1-3 mg/mL) increases cAMP levels in isolated tracheal homogenates, similar to positive control phosphodiesterase inhibitor (papaverine). When tested for antibacterial activity against standard and clinical strains, Of.Cr was found more active (MIC 475 µg/ml) against S. aureus (NCTC 6571), while the maximum inhibition (MIC 625 µg/ml) was observed by the extract when tested against MRSA. These results determine the mechanistic pathways of the observed bronchodilatory effect of Otostegia fruticosa with a combination of anticholinergic and dual inhibition of phosphodiesterase and voltage-gated Ca++ channels.

Antimalarial Activity of Meriandra dianthera Leaf Extracts in Plasmodium berghei-Infected Mice.

OBJECTIVE: To evaluate the antimalarial effect of aqueous methanolic extract and solvent fractions of Meriandra dianthera leaves against Plasmodium berghei in mice model. METHOD: M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the in vivo antimalarial activity of the extract and fractions. RESULT: The crude leaf extract of Meriandra dianthera leaves against P < 0.001) chemosuppression compared to the negative control. Both the extract and fractions were able to prevent P. berghei induced body weight loss and body temperature reduction and also increased the survival time of the mice as compared to the negative control. The aqueous methanolic leaf extract of M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the. CONCLUSION: The extracts of M. dianthera leaves showed promising antimalarial activity, with no sign of toxicity and therefore may support its traditional use for the treatment of malaria.M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the.

Evaluation of in vitro α-amylase inhibitory activity and antidiabetic effect of Myrica salicifolia in streptozotocin-induced diabetic mice.

The study was aimed to evaluate in vitro antioxidant, α-amylase inhibitory and in vivo antidiabetic activities of Myrica salicifolia root extracts. The powdered roots of M. salicifolia were extracted with 80% methanol and then dried. The dried extract was further fractionated into chloroform, ethyl acetate, butanol and aqueous fractions. The phytochemical screening of the crude extract was performed using standard chemical identification tests. The antioxidant activity of the extracts was determined by in vitro method using 2,2-diphenyl-1-picrylhydrazyl (DPPH) as radical scavenging reagent. The in vitro α-amylase inhibitory activity was performed using the chromogenic3,5-dinitrosalicylic (DNSA) method. The antidiabetic activity of M. salicifolia root crude extract (200, 400 and 600 mg/kg) and fractions (400 mg/kg) were evaluated in normal, glucose loaded hyperglycemic and streptozotocin (STZ)-induced diabetic mice. The crude root extract of M. salicifolia showed strong DPPH radical scavenging activity (IC50 = 4.54µg/ml) which was comparable with the standard antioxidant, ascorbic acid. In α-amylase inhibitory activity, the crude extract and butanol fraction showed highest enzyme inhibition. In the antidiabetic activity, daily administration of the crude extract, aqueous and butanol fractions for fifteen days showed highest significant reduction in fasting blood glucose level (BGL) compared to diabetic control in STZ-induced diabetic mice model. The root extract and fractions of M. salicifolia exhibited significant antihyperglycemic, α-amylase inhibitory and antioxidant activity with no sign of toxicity. The antidiabetic effect of the plant could be due to the synergistic effect of various classes of constituents present in the root part of the plant.

Nigella sativa L. (Black Cumin): A Promising Natural Remedy for Wide Range of Illnesses.

The seed of Nigella sativa (N. sativa) has been used in different civilization around the world for centuries to treat various animal and human ailments. So far, numerous studies demonstrated the seed of Nigella sativa and its main active constituent, thymoquinone, to be medicinally very effective against various illnesses including different chronic illness: neurological and mental illness, cardiovascular disorders, cancer, diabetes, inflammatory conditions, and infertility as well as various infectious diseases due to bacterial, fungal, parasitic, and viral infections. In spite of limited studies conducted so far, the promising efficacy of N. sativa against HIV/AIDS can be explored as an alternative option for the treatment of this pandemic disease after substantiating its full therapeutic efficacy. Moreover, the strong antioxidant property of this valued seed has recently gained increasing attention with regard to its potential role as dietary supplement with minimal side effects. Besides, when combined with different conventional chemotherapeutic agents, it synergizes their effects resulting in reducing the dosage of concomitantly used drugs with optimized efficacy and least and/or no toxicity. A number of pharmaceutical and biological properties have been ascribed to seeds of N. sativa. The present review focuses on the profile of high-value components along with traditional medicinal and biological principles of N. sativa seed and its oil so as to explore functional food and nutraceutical potential of this valued herb.

Evaluation of Antimalarial Activity of the Leaf Latex and TLC Isolates from Aloe megalacantha Baker in Plasmodium berghei Infected Mice.

Malaria is a devastating parasitic disease which caused around 216 million cases and 445,000 deaths worldwide in 2016. This might be attributed to a wide spread of drug resistant parasites. The plant Aloe megalacantha is indigenous to Ethiopia where the sap of the leaves is traditionally used for the treatment of malaria. This study was aimed at evaluating the antimalarial effect of leaf latex and isolates obtained from Aloe megalacantha against chloroquine sensitive Plasmodium berghei ANKA strain in Swiss albino mice. Peters' 4-day suppressive test method was used to test the antimalarial activity of both leaves latex and isolates. Three isolates were obtained using thin layer chromatography and were coded as AM1, AM2, and AM3 in ascending order of their retention factor. After treatment of Plasmodium berghei infected mice with leaf latex of Aloe megalacantha for four days at 100, 200, and 400 mg/kg, it shows 30.3%, 43.4%, and 56.4% suppression of the parasite growth, respectively. 32.3%, 51.3%, and 67.4% chemosuppression after treatment with AM1, 39.8%, 50.6%, and 64.2% chemosuppression after treatment with AM2, and 52.6%, 69.4%, and 79.6% chemosuppression after treatment with AM3 were observed at doses of 100, 200, and 400 mg/kg/day, respectively. The observed parasite suppression of leaves latex and isolates was statistically significant (P<0.05) as compared to negative control. Moreover, both the leaves latex and isolates were also observed to prevent Plasmodium berghei induced body weight loss and hypothermia and increased the survival time of Plasmodium berghei infected mice as compared to the negative control. Hence, the present study supports the traditional claim of the plant for the treatment of malaria.

Pregnane derivatives from Potentilla evestita.

A new pregnane derivative, 2,6beta,7beta-trihydroxy-4-methyl-19-norpregna-1,3,5(10)-trien-17-one, has been isolated from the ethyl acetate soluble fraction of Potentilla evestita along with a pregnane derivative, 11alpha,17alpha,21-trihydroxypregna-4,16(22)-diene-3,20-dione, that is reported for the first time as a natural product. Their structures were elucidated with the aid of 1H and 13C NMR spectra and by COSY, HMQC, HMBC and NOESY experiments.

Barlerisides A and B, new potent superoxide scavenging phenolic glycosides from Barleria acanthoides.

Barlerisides A (1) and B (2), new phenolic glycosides, have been isolated from the n-butanol soluble sub-fraction of Barleria acanthoides along with two known compounds acteoside (3) and p-hydroxycinnamic acid (4). Their structures have been assigned on the basis of spectral studies. Both 1 and 2 showed significant activity in the superoxide scavenging assay while weak inhibitory activity was observed against the enzyme xanthine oxidase.