A comparative study of in-vitro and in-silico anti-candidal activity and GC-MS profiles of snow mountain garlic vs. normal garlic.

AIM: The study aimed to profile the volatile phytocomposition of snow mountain garlic (SMG) compared to normal garlic and investigate the anti-Candida efficacy against clinically relevant multi-drug resistant isolates of Candida species. METHODS AND RESULTS: Herein, SMG has shown significantly superior fungicidal power at 2x-MIC dose against C. albicans and C. glabrata in killing kinetic evaluation unlike the fungistatic effect of normal garlic. GC-MS headspace-based profiling of SMG showed 5 unique volatile compounds and a 5-fold higher content of saponins than normal garlic. In an in-silico analysis, cholesta-4,6-dien-3-ol,(3-beta) was uniquely identified in SMG as a potential inhibitor with high binding affinity to the active site of exo-1,3-betaglucan synthase, an established anti-candida drug target crucial for the biofilm matrix formation, thus suggesting a plausible anti-Candida mechanism. CONCLUSION: The in-vitro and in-silico studies have demonstrated the Candida-cidal and anti-biofilm activities of SMG, distinguishing it from the Candida-static efficacy of normal garlic. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report that identifies several phytochemical signatures of SMG along with a potential anti-Candida compound, that is cholesta-4,6-dien-3-ol,(3-beta)-, which appears worthy of detailed studies in the future to explore the utility of SMG as a fungal phytotherapy agent, especially against drug-resistant Candida sp.

Green synthesis of silver nanoparticles using Rhodiola imbricata and Withania somnifera root extract and their potential catalytic, antioxidant, cytotoxic and growth-promoting activities.

This study presents the development of a sustainable production process of environmentally benign silver nanoparticles (AgNPs) from aqueous root extract of Rhodiola imbricata (RI) and Withania somnifera (WS) for mitigating environmental pollution and investigating their potential applications in agriculture and biomedical industry. RIWS-AgNPs were characterized using several analytical techniques (UV-Vis, DLS, HR-TEM, SAED, EDX and FTIR). The antioxidant and anticancer activity of RIWS-AgNPs were estimated by DPPH and MTT assay, respectively. UV-Vis and DLS analysis indicated that equal ratio of RIWS-extract and silver nitrate (1:1) is optimum for green synthesis of well-dispersed AgNPs (λmax: 430 nm, polydispersity index: 0.179, zeta potential: - 17.9 ± 4.14). HR-TEM and SAED analysis confirmed the formation of spherical and crystalline RIWS-AgNPs (37-42 nm). FTIR analysis demonstrated that the phenolic compounds are probably involved in stabilization of RIWS-AgNPs. RIWS-AgNPs showed effective catalytic degradation of hazardous environmental pollutant (4-nitrophenol). RIWS-AgNPs treatment significantly increased the growth and photosynthetic pigments of Hordeum vulgare in a size- and dose-dependent manner (germination (77%), chlorophyll a (12.62 ± 0.07 µg/ml) and total carotenoids (7.05 ± 0.04 µg/ml)). The DPPH assay demonstrated that RIWS-AgNPs exert concentration-dependent potent antioxidant activity (IC50: 12.30 µg/ml, EC50: 0.104 mg/ml, ARP: 959.45). Moreover, RIWS-AgNPs also confer strong cytotoxic activity against HepG2 cancer cell line in dose-dependent manner (cell viability: 9.51 ± 1.55%). Overall, the present study for the first time demonstrated a green technology for the synthesis of stable RIWS-AgNPs and their potential applications in biomedical and agriculture industry as phytostimulatory, antioxidant and anticancer agent. Moreover, RIWS-AgNPs could potentially be used as a green alternative for environmental remediation.

Class switching of carbonic anhydrase isoforms mediates remyelination in CA3 hippocampal neurons during chronic hypoxia.

Chronic exposure to hypoxia results in cerebral white matter hyperintensities, increased P300 latency, delayed response and impairment in working memory. Despite burgeoning evidence on role of myelination in nerve conduction, the effect of chronic hypoxia on myelination of hippocampal neurons has been less studied. The present study provides novel evidence on alterations in myelination of hippocampal CA3 neurons following chronic hypoxic exposure. Sprague Dawley rats exposed to global hypobaric hypoxia simulating altitude of 25,000 ft showed progressive demyelination in CA3 hippocampal neurons on 14 days followed by remyelination on 21 and 28 days. The demyelination of CA3 neurons was associated with increased apoptosis of both oligodendrocyte precursor cells (OPCs) and mature oligodendrocytes (OLs), peroxidation of myelin lipids, and nitration induced reduced expression of Carbonic Anhydrase II (CAII). Prolonged hypoxic exposure of 21 and 28 days on the other hand resulted in peroxisome proliferator-activated receptor alpha (PPARα) induced upregulation of Carbonic Anhydrase IV (CAIV) expression in mature oligodendrocytes through iNOS mediated mechanisms along with reduction in lipid peroxidation and remyelination. Inhibition of carbonic anhydrase activity on the other hand prevented remyelination of CA3 neurons. Based on these findings we propose a novel iNOS mediated mechanism for regulation of myelination in hypoxic hippocampal neurons through class switching of carbonic anhydrases.

ELONGATED HYPOCOTYL5 Negatively Regulates DECREASE WAX BIOSYNTHESIS to Increase Survival during UV-B Stress.

Understanding how the distinct cell types of the shoot apical meristem (SAM) withstand ultraviolet radiation (UVR) stress can improve cultivation of plants in high-UVR environments. Here, we show that UV-B irradiation selectively kills epidermal and niche cells in the shoot apex. Plants harboring a mutation in DECREASE WAX BIOSYNTHESIS (DEWAX) are tolerant to UV-B. Our data show that DEWAX negatively regulates genes involved in anthocyanin biosynthesis. ELONGATED HYPOCOTYL5 (HY5) binds to the DEWAX promoter elements and represses its expression to promote the anthocyanin biosynthesis. The HY5-DEWAX regulatory network regulates anthocyanin content in Arabidopsis (Arabidopsis thaliana) and influences the survivability of plants under UV-B irradiation stress. Our cell sorting-based study of the epidermal cell layer transcriptome confirms that core UV-B stress signaling pathway genes are conserved and upregulated in response to UV-B irradiation of the SAM. Furthermore, we show that UV-B induces genes involved in shoot development and organ patterning. We propose that the HY5-DEWAX regulatory relationship is conserved; however, changes in the expression levels of these genes can determine anthocyanin content in planta and, hence, fitness under UV-B irradiation stress.

Morphometric, haematological and physio-biochemical characterization of Bactrian (Camelus bactrianus) camel at high altitude.

BACKGROUND: Biochemical and haematological parameters have not been determined in Bactrian camels kept at high altitude. Therefore, this study was undertaken to characterise different physiological, haematological, biochemical, and morphometric parameters of Bactrian camels of high altitude. For this, total fourteen high altitude healthy Bactrian camels were selected from Leh-Ladakh, India, a high altitude area, and thereafter divided into three age groups (N = 3 young; N = 6 adult; N = 5 old camels) to characterise for above parameters. All the results were compared with Lowlander Bactrian camels. RESULTS: Morphometric measurement showed significant difference in body height, body length, front-hump height and girth, back-hump height and girth, abdomen girth, neck length, and circumference of the shank in the young age group camels as compared to other age groups of Bactrian camels (p < 0.05). Furthermore, all the physiological and haematological parameters were similar in all the age groups of camels (p < 0.05). However, the leukocyte, erythrocyte, Hb, platelets, monocyte, and ESR level were towards the higher side of the normal reference range of Lowlander Bactrian camels. Whereas, the biochemical analysis revealed a significant increase in triglycerides and decrease in protein levels in the younger age group as compared to other age groups (p < 0.05). Although, albumin, aspartate aminotransferase, iron, magnesium, urea, and creatinine levels were insignificant among the different groups, but observed towards the higher side of the low altitude reference range. Interestingly, the glucose levels in all the groups were observed towards the lower side of the range, which showed metabolic adaptation to high altitude. CONCLUSION: These findings suggested there is morphometric and biochemical variation in Bactrian camel of high altitude. The results further helped in establishing novel reference ranges for these parameters in Highlander Bactrian camel. Hence, this study will be the basis of future research on a Bactrian camel from high-altitude cold desert and helpful for better camel husbandry and health management in high altitude.

Methanolic root extract of Codonopsis clematidea prevents hypoxia induced procoagulant state by inhibition of GPIb receptor regulated Lyn kinase activation.

BACKGROUND: The prevalence of procoagulant state under prolonged hypoxic exposures and the complications and lack of specificity associated with use of existing anti-thrombotic agents have necessitated the search for safer and natural therapeutics. Codonopsis, a widely studied medicinal herb, has been reported to decrease whole blood viscosity but the bioactive ingredients involved, and their mechanism of action therein however remain to be investigated. PURPOSE: The present study aimed at evaluating the efficacy of C. clematidea root extract and mechanism of action of its bioactive constituent flavonoid, Kaempferol, in ameliorating hypobaric hypoxia induced procoagulant state. METHODS: Fingerprinting analysis of methanolic extract of C. clematidea root was performed by RP-HPLC. In vitro toxicity study was conducted using HUVEC cell line and in vivo acute and sub-acute toxicity were done according to OECD guidelines (section-4, number-420 and 407 respectively). Adult male Sprague-Dawley rats weighing 230-250 g were exposed to global hypoxia simulating an altitude of 7600 m (282 mmHg), in animal decompression chamber for 3, 7, 14 and 21 days for in vivo studies. Dose optimisation of the extract was done by quantification of Thromboxane A2 in the serum of hypoxic rats. C. clematidea root extract was also evaluated for its in vitro and in vivo antioxidant properties. Procoagulant changes were studied by biochemical plasma coagulation assays and expression analysis of the signalling molecules of the platelet activation cascade like vWF, platelet activation marker CD41, GpIb-IX-V (CD42), Lyn kinase, p-PI3K, p-ERK and p-PLCγ were conducted to investigate C. clematidea mediated signalling mechanisms. RESULTS: Methanolic extract of C. clematidea root showed improved antioxidant status and improvement in bleeding time and in vitro coagulation assays like pT, aPTT, INR. Decreased concentrations of D-Dimers along with that of platelet activation marker CD41 and serum concentration of Thromboxane A2 were observed in C. clematidea root extract supplemented hypoxic animals. Phosphorylation of Lyn kinase, was reduced despite increase in concentration of activating ligand vWF. CONCLUSION: C. clematidea root extract was effective in preventing hypoxia induced platelet activation and resultant procoagulant state by inhibiting Lyn kinase, a serine threonine kinase effector of vWF signalling cascade.

Hypoxia-mediated alteration in cholesterol oxidation and raft dynamics regulates BDNF signalling and neurodegeneration in hippocampus.

Brain-derived neurotrophic factor (BDNF) which is primarily associated with neuronal survivability, differentiation and synaptic plasticity has been reported to mediate neurodegeneration in hypoxia through its p75 Neurotrophin receptors (p75NTR). The molecular events promoting BDNF-mediated pro-death signalling in hypoxia, however, still remain an enigma. This study attempts towards deciphering the signalling cascades involved in alteration of BDNF isoforms and its cognate receptor subtypes leading to neurodegeneration in hypoxia. Adult Sprague-Dawley rats were exposed to global hypobaric hypoxia simulating an altitude of 7620 m at standard temperature and humidity. Chronic hypoxic exposure for 7 days resulted in higher expression of pro-BDNF and alteration in N-linked glycosylation in hippocampus along with increased expression of endoplasmic reticulum stress markers viz., glucose-regulated protein (Grp78), calnexin and changes in the endoplasmic reticulum morphology. Our findings reveal enriched expression of p75NTR in lipid rafts and higher expression of tyrosine receptor kinase ß (Trkß) in non-raft regions following hypoxic exposure. Further investigations on membrane properties revealed decline in membrane fluidity along with increased cholesterol oxidation resulting in reduced translocation of Trkß from non-raft to raft regions. Supplementation of vitamin E during hypoxic exposure on the other hand reduced cholesterol oxidation and increased translocation of Trkß from non-raft to raft regions and promoted neuronal survival. Hence, our findings suggest a novel mechanism of cholesterol oxidation-induced alteration in raft dynamics which is promotes p75 receptor-mediated death signalling in hippocampal neurons during chronic hypoxia.

Enhanced Production of Phenolic Compounds in Compact Callus Aggregate Suspension Cultures of Rhodiola imbricata Edgew.

Rhodiola imbricata is a rare medicinal plant of the trans-Himalayan region of Ladakh. It is used for the treatment of numerous health ailments. Compact callus aggregate (CCA) suspension cultures of Rhodiola imbricata were established to counter extinction threats and for production of therapeutically valuable phenolic compounds to meet their increasing industrial demands. The present study also investigated the effect of jasmonic acid (JA) on production of phenolic compounds and bioactivities in CCA suspension cultures. CCA suspension cultures established in an optimized Murashige and Skoog medium supplemented with 30 g/l sucrose, 3 mg/l NAA, and 3 mg/l BAP showed maximum biomass accumulation (8.43 g/l DW) and highest salidroside production (3.37 mg/g DW). Upon 100 µM JA treatment, salidroside production (5.25 mg/g DW), total phenolic content (14.69 mg CHA/g DW), total flavonoid content (4.95 mg RE/g DW), and ascorbic acid content (17.93 mg/g DW) were significantly increased in cultures. In addition, DPPH-scavenging activity (56.32%) and total antioxidant capacity (60.45 mg QE/g DW) were significantly enhanced upon JA treatment, and this was positively correlated with increased accumulation of phenolic compounds. JA-elicited cultures exhibited highest antimicrobial activity against Escherichia coli. This is the first report describing the enhanced production of phenolic compounds and bioactivities from JA-elicited CCA suspension cultures of Rhodiola imbricata.

Kaempferol Inhibits Extra-synaptic NMDAR-Mediated Downregulation of TRkß in Rat Hippocampus During Hypoxia.

Cognitive dysfunction on chronic exposure to hypobaric hypoxia has been attributed to a myriad of survival and degenerative factors. Downregulation of Trkß and compromised survival signaling has been ascribed as a major contributing factor for hypoxic neurodegeneration. The mechanisms leading to downregulation of Trkß in hypoxia, however, remain to be elucidated. The present study aimed at investigating the upstream signaling mechanisms leading to Trkß downregulation in hypoxia and the potential of Kaempferol in ameliorating these changes. Our results showed a duration-dependent increase in hypoxic neurodegeneration as measured by Fluoro-Jade C staining of hippocampal CA3 neurons. Protein expression studies revealed strong correlation of Trkß with NR1 and NR2b expression on exposure to hypoxic stress. Administration of Kaempferol during hypoxic stress revealed its neuroprotective effect and Morris Water Maze test also highlighted its efficacy in improving spatial learning and memory. Further elucidation of the signaling mechanisms using specific inhibitors and in vitro silencing experiments confirmed involvement of extra-synaptic N-methyl-d-aspartate receptor (NMDAR) i.e. NR2b receptor subunit in downregulation of Trkß under hypoxic conditions. ChIP assay showed involvement of E47 transcription factor in NR2b mediated Trkß downregulation. Selective inhibition of signaling intermediate MLK2 by CEP11004 and inhibition of extra-synaptic NMDAR during hypoxic stress prevented Trkß downregulation in the hippocampus of hypoxic rats. Administration of Kaempferol also inhibited phosphorylation of E47 and hypoxia-induced downregulation of Trkß. The present study establishes the role of extra-synaptic NMDAR in hypoxia-induced downregulation of Trkß and the efficacy of Kaempferol in inhibiting extra-synaptic NMDAR-mediated signaling.

Influence of light quality on growth, secondary metabolites production and antioxidant activity in callus culture of Rhodiola imbricata Edgew.

Rhodiola imbricata is a rare medicinal herb well-known for its adaptogenic and antioxidant properties due to the presence of a diverse array of secondary metabolites, including phenylethanoids and phenylpropanoids. These secondary metabolites are generating considerable interest due to their potential applications in pharmaceutical and nutraceutical industries. The present study investigated the influence of light quality on growth, production of industrially important secondary metabolites and antioxidant activity in callus cultures of Rhodiola imbricata. Callus cultures of Rhodiola imbricata were established under different light conditions: 100% red, 100% blue, 100% green, RGB (40% red: 40% green: 20% blue) and 100% white (control). The results showed that the callus cultures grown under red light accumulated maximum amount of biomass (7.43 g/l) on day 21 of culture, as compared to other light conditions. Maximum specific growth rate (0.126 days-1) and doubling time (132.66 h) was observed in callus cultures grown under red light. Reverse phase-high performance liquid chromatographic (RP-HPLC) analysis revealed that the callus cultures exposed to blue light accumulated maximum amount of Salidroside (3.12 mg/g DW) on day 21 of culture, as compared to other light conditions. UV-Vis spectrophotometric analysis showed that the callus cultures exposed to blue light accumulated maximum amount of total phenolics (11.84 mg CHA/g DW) and total flavonoids (5.53 mg RE/g DW), as compared to other light conditions. Additionally, callus cultures grown under blue light displayed enhanced DPPH free radical scavenging activity (53.50%). Callus cultures grown under different light conditions showed no significant difference in ascorbic acid content (11.05-13.90 mg/g DW) and total antioxidant capacity (27.37-30.17 mg QE/g DW). The correlation analysis showed a positive correlation between total phenolic content and DPPH free radical scavenging activity in callus cultures (r = 0.85). Taken together, these results demonstrate the remarkable potential of light quality on biomass accumulation and production of industrially important secondary metabolites in callus cultures of Rhodiola imbricata. This study will open new avenues and perspectives towards abiotic elicitation strategies for sustainable growth and enhanced production of bioactive compounds in in-vitro cultures of Rhodiola imbricata.

Prevalence and risk factors of hypertension in acclimatized lowlanders staying at high altitude for different durations.

Hypoxic exposure at high-altitude (HA) modulates blood pressure (BP). High prevalence of hypertension among native highlanders (NH) has been reported. However, information on prevalence and determinants of hypertension in acclimatized young lowlanders (ALL) staying at HA for different durations is sparse. We aimed to determine the prevalence of hypertension in ALL staying at HA for different durations and its association with cardiovascular risk factors. Male volunteers were categorized on the basis of their duration of stay at HA; Lowlanders (LL) (0 months; n = 151), ALL (1-24 months; n = 519) and NH (n = 103). ALL were sub grouped into ALL 1 (1-6 months; n = 165), ALL 2 (6-12 months; n = 181), and ALL 3 (12-24 months; n = 173). BP, sympathetic activity, arterial stiffness, lipid profile, and homocysteine were estimated. Regression analysis was performed to determine association of risk factors with hypertension. Prevalence of hypertension among ALL was highest with 17.53% followed by NH (11.6%) and LL (9.27%). Prevalence of hypertension in ALL sub group was in order ALL 1 < ALL 2 < ALL 3. Hypertension was significantly associated with sympathetic dominance (p < 0.001) in ALL 1. Hypertension in ALL 2 was associated with dyslipidemia (p < 0.01) while in ALL 3 hypertension was associated with hyperhomocysteinemia (hHCY, p < 0.001), arterial stiffness and dyslipidemia (p < 0.01). In conclusion, our report suggests higher prevalence of hypertension in ALL. The association of studied risk factors and hypertension in different ALL sub groups varied significantly. Our findings suggest the need for a differential clinical approach to control hypertension in ALL considering their duration of stay at HA.

Estrogen Receptor ß Mediated Neuroprotective Efficacy of Cicer microphyllum Seed Extract in Global Hypoxia.

Hypoxia induced oxidative stress and neurodegeneration in the hippocampus has been implicated for memory impairment in conditions like stroke, ischemia and hypobaric hypoxia. The present study, aimed at investigating the potential of ethanolic extract of Cicer microphyllum seeds (CSE) for amelioration of global hypoxia induced neurodegeneration in CA1 region of hippocampus. CSE supplementation considerably reduced neurodegeneration and dendritic atrophy in CA1 neurons along with improvement of memory in hypoxic rats. This effect of CSE was partly attributed to its antioxidant activity resulting in reduction of lipid peroxidation, protein oxidation and DNA damage during exposure to chronic hypoxia. CSE also promoted dendritic arborization through activation of estrogen receptor beta (ERß) and phosphorylation of extracellular signal regulated kinase (ERK1/2) which was independent of brain derived neurotrophic factor (BDNF) mediated signalling mechanisms. Extra nuclear activation of ERK1/2 by ERß resulted in phosphorylation of cyclic AMP response element binding protein (CREB) leading to increased expression of PSD-95.These molecular alterations translated to behavioural changes in CSE administered hypoxic animals that performed better in Morris Water Maze Task as compared to vehicle treated hypoxic animals. Toxicological studies show NOEAL > 2000 mg/kg b.w. for oral administration of CSE indicating its safety for consumption. Our findings not only suggest the neuroprotective potential of CSE in hypoxia but also provide evidence for involvement of estrogen receptor and pCREB mediated nootropic effect of the extract.

Effect of seabuckthorn seed oil in reducing cardiovascular risk factors: A longitudinal controlled trial on hypertensive subjects.

BACKGROUND & AIMS: The present study aimed at investigating whether dietary supplementation of seabuckthorn seed oil which is rich in omega fatty acids at an oral dose of 0.75 ml could affect cardiovascular risk factors and reduce hypertension and systolic blood pressure. METHODS: Toxicological evaluation and efficacy of seabuckthorn seed oil in reducing high fat diet induced dyslipidemia was initially conducted on adult male Sprague Dawley rats. 32 normal and 74 hypertensive and hypercholestrolemic human subjects participated in the randomized, controlled, double blind longitudinal study. Seabuckthorn seed oil or sunflower oil placebo was orally supplemented at a daily dose of 0.75 ml for 30 days. RESULTS: Supplementation of seabuckthorn seed oil at a daily dose of 0.75 ml for 30 days resulted in normalization of blood pressure in hypertensive subjects. Dietary supplementation of seabuckthorn seed oil markedly reduces cholesterol, oxy-LDL and triglycerides in hypercholesterolemic subjects though it's effect on subjects with normal blood pressure and cholesterol is less pronounced. Seabuckthorn seed oil supplementation also improves circulatory antioxidant status in both normal and hypertensive subjects. CONCLUSION: The present study demonstrates the efficacy of seabuckthorn seed oil in reducing dyslipidemia, cardiovascular risk factors and hypertension in human population which may be due to presence of omega 3, 6 and 9 fatty acids in the oil. The improvement in antioxidant status can be attributed to presence of beta carotene and vitamin E in seabuckthorn seed oil. The trial was registered with Clinical Trial Registry of India (Clinical trial registration number - CTRI/2015/11/006368).

Chemical composition and antioxidant capacities of phytococktail extracts from trans-Himalayan cold desert.

BACKGROUND: Himalayan plants are widely used in traditional system of medicine both as prophylactics and therapeutics for high altitude maladies. Our aim was to evaluate the antioxidant capacities and bioactive compounds of methanol and n-hexane extracts of the phytococktail comprising of sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca) and roseroot (Rhodiola imbricata) from trans-Himalaya. METHODS: The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and nitric oxide (NO) radical scavenging capacities and lipid peroxidation inhibition (LPI) property of the extracts were determined. Total antioxidant power was determined by ferric reducing/antioxidant power (FRAP) assay. Total polyphenol, flavonoid, flavonol, proanthocyanidin and carotenoid were also estimated for both extracts. We have identified and quantified the phyto-chemotypes present in the methanol and n-hexane extracts by hyphenated gas chromatography/mass spectrometry (GC/MS) technique. RESULTS: Antioxidant capacity assays using DPPH, ABTS, NO, LPI and FRAP exhibited analogous results where the phytococktail showed high antioxidant action. The phytococktail was also found to possess high quantity of total polyphenol, flavonoid, flavonol and carotenoid. A significant and linear correlation was found between the antioxidant capacities and bioactive principles. A total of 32 phyto-chemotypes were identified from these extracts by GC/MS chemometric fingerprinting. Major phyto-chemotypes identified by GC/MS were glycosides, phenylpropanoids and derivatives, terpenoids, alkaloids, phytosterols, fatty acids and esters, alkaloids and derivatives, organic acid esters and aromatic ethers with positive biological and pharmacological actions. CONCLUSION: The phytococktail extracts were found to contain considerable amount of diverse bioactive compounds with high antioxidant capacities. The presence of hydrophilic and lipophilic antioxidants in the phytococktail could have contributed to the higher antioxidant values. Hence, the phytococktail could be used as natural source of antioxidants to ameliorate disorders associated with oxidative stress.

Free radical scavenging property and antiproliferative activity of Rhodiola imbricata Edgew extracts in HT-29 human colon cancer cells.

OBJECTIVE: To investigate the in vitro antioxidant and antiproliferative activity of rhizome extracts of Rhodiola imbricata (R. imbricata) in HT-29 human colon cancer cell line. METHODS: The successively extracted rhizome of R. imbricata using various solvents was analyzed for their total phenolics, tannins and flavonoid contents. In vitro antioxidant activity was evaluated by employing different assays, including DPPH, ABTS radical scavenging assays, FRAP, phosphomolybdenum reduction assay, superoxide anion, hydroxyl radical scavenging activities and metal chelating ability. RESULTS: Acetone and methanol extracts recorded higher phenolic content and showed comparable antioxidant activity with standard reference. Additionally, they also inhibited the proliferation of HT-29 cells upon treatment at higher concentration (200 µg/mL) (acetone and methanol, 84% and 84%, respectively). On examination acetone extract exhibited antiproliferative activity in a concentration dependent manner whereas, methanol extract showed both dose dependent and time dependent inhibitory activity. CONCLUSIONS: The results obtained justify the traditional usage of R. imbricata from their promising antioxidant activity.

Acute and sub acute toxicity and efficacy studies of Hippophae rhamnoides based herbal antioxidant supplement.

OBJECTIVES: Present study was carried out to evaluate acute and subacute toxicity and efficacy of Seabuckthorn (Hippophae rhamnoides) based herbal antioxidant supplement (HAOS). MATERIALS AND METHODS: In vivo toxicity studies were performed in male balb 'C' mice by oral administration. Acute toxicity study was done at doses ranging from 2000 to 10 000 mg/ kg while in subacute studies, HAOS was given at doses of 2000, 4000, and 8000 mg/kg body weight. Animals were observed for any toxic sign and symptoms periodically. At completion of study animals were sacrificed; their hematological, biochemical parameters were analyzed and histopathology of vital organs was done. In vivo efficacy studies in human volunteers were done and the levels of vitamin A and Vitamin C in blood samples were analyzed in comparison to a similar commercially available formulation. RESULTS: No mortality and any clinical signs of toxicity were found in HAOS administered group of animals. There were no significant alterations in hematological and biochemical parameters. Histopathological analysis of vital organs showed normal architecture in all the HAOS administered groups. Human studies showed an increase of 32% and 172% in Vitamin A and Vitamin C levels respectively in term of bioavailability. CONCLUSION: The data obtained indicate no toxicity of this antioxidant supplement up to the highest dose studied. Efficacy in terms of increased bioavailability of vitamin A and C in human volunteers indicates the clinical usefulness of the supplement.

Acetyl-L-carnitine-mediated neuroprotection during hypoxia is attributed to ERK1/2-Nrf2-regulated mitochondrial biosynthesis.

Neuronal damage in hypoxia and several neurodegenerative disorders is invariably associated with oxidative damage and mitochondrial dysfunction. Administration of acetyl-L-carnitine (ALCAR) on the other hand attenuates neuronal damage, prevents apoptosis, and improves energy status in hypoxic stress through less understood mechanisms. Becasue mitochondrial biogenesis could be a possible mechanism for ALCAR-induced improvement in bioenergetics in neurons, the present study aimed at exploring signaling pathways of ALCAR-induced neuroprotection in hypoxia and possible occurrence of mitochondrial biogenesis. To create global hypoxia, adult Sprague-Dawley rats were exposed to a simulated altitude of 7,620 m at standard temperature and humidity conditions. We here demonstrate that administration of ALCAR to hypoxic rats for a period of 2 weeks effectively protected hippocampal neurons from mitochondrial dysfunction, excitotoxicity, and neurodegeneration. ALCAR administration resulted in peroxisome proliferator-activated receptor γ coactivator-1α and nuclear respiratory factor-1-induced mitochondrial biogenesis, the expression of which was regulated by an extracellular-related kinase-nuclear factor erythroid 2-related factor 2 (ERK-Nrf2)-mediated mechanism. Most notably, calcium buffering into nonfunctional mitochondria ameliorated excitotoxicity and improved bioenergetic status of the hippocampal neurons. Together, the data reveal the immense therapeutic potential of ALCAR for the treatment of ischemia, stroke, and other neurodegenerative disorders associated with hypoxic stress and excitotoxicity.