Phytochemicals and in vitro antioxidant potentials of defatted methanolic extract ofHolarrhena floribunda leaves

Plant-based dietary components and additives are known to protect cells from deleterious effect of reactive oxygen species (ROS). Proximate, phytochemical and antioxidant potentials of methanolic extract of defatted Holarrhena floribunda (G.Don) leaves were assessed using in vitro systems such as, 1,1 diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, nitric oxide radical scavenging and inhibition of lipid peroxidation. Total antioxidant activity was measured using phosphomolybdenummethod. Total phenol content and the reductive potential of the extract were also evaluated. The results of the proximate analysis revealed that the leaf contained 0.23% moisture, 12.8% ash, 9.62% crude fat, 23.3% crude fibre, 21.17% protein and 32.68% carbohydrate while the phytochemical constituents included alkaloid, saponin, tannin and cardiac glycosides. The leaf extract of H. floribunda (G. Don) exhibited scavenging activity with IC50 of 12.63, 1,377.00 and 244.00 ìg/ml for DPPH, hydroxyl radical and nitric oxide radical respectively. The extract conferred 50% protection at the concentration of 73.80 ìg/ml on lipid peroxidation induced by FeSO4 in egg yolk. Total antioxidant capacity equivalent of gallicacid and vitamin C were 195.57 and 519.28 g/mg of extract respectively and total phenol content equivalent of gallic acid was 1427.87 ìg/mg. The reductive potential increased with increasing concentration of extract. The results obtained from this study reveal that the extract is rich inantioxidant components with several mechanisms of eliciting antioxidant actions which provide scientific basis for its use in folk medicine

Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves.

Bioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrhena floribunda. The antioxidant capacity using the ORAC, FRAP and TEAC assays and inhibition of lipid peroxidation were measured for isolated flavonoids. The result showed that compounds 2 and 4 showed significantly increased ORAC, TEAC, and FRAP activities with low pro-oxidant potential as well as improved lipid peroxidation inhibition levels when compared to compounds 1 and 3. The most active compounds were found to be flavonoids with a quercetin basic structure. These results imply that the isolated flavonoid glycosides are responsible for the antioxidant activity of the plant leaves and it forms the scientific basis for its traditional usage

Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves

ArticleBioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrhena floribunda. The antioxidant capacity using the ORAC, FRAP and TEAC assays and inhibition of lipid peroxidation were measured for isolated flavonoids. The result showed that compounds 2 and 4 showed significantly increased ORAC, TEAC, and FRAP activities with low pro-oxidant potential as well as improved lipid peroxidation inhibition levels when compared to compounds 1 and 3. The most active compounds were found to be flavonoids with a quercetin basic structure. These results imply that the isolated flavonoid glycosides are responsible for the antioxidant activity of the plant leaves and it forms the scientific basis for its traditional usage.TETFund (Nigeria) for PhD travel scholarship granted to the first author.Sponsored, in part, by the National Research Foundation (NRF), South Afric

Analysis of the frequency and spectrum of mutations recognised to cause familial hypercholesterolaemia in routine clinical practice in a UK specialist hospital lipid clinic

Aim: To determine the frequency and spectrum of mutations causing Familial Hypercholesterolaemia (FH) in patients attending a single UK specialist hospital lipid clinic in Oxford and to identify characteristics contributing to a high mutation detection rate. Methods: 289 patients (272 probands) were screened sequentially over a 2-year period for mutations in LDLR, APOB and PCSK9 using standard molecular genetic techniques. The Simon Broome (SB) clinical diagnostic criteria were used to classify patients and a separate cohort of 409 FH patients was used for replication. Results: An FH-causing mutation was found in 101 unrelated patients (LDLR=54 different mutations, APOB p.(Arg3527Gln)=10, PCSK9 p.(Asp374Tyr)=0). In the 60 SB Definite FH patients the mutation detection rate was 73% while in the 142 with Possible FH the rate was significantly lower (27%, p<0.0001), but similar (14%, p=0.06) to the 70 in whom there was insufficient data to make a clinical diagnosis. The mutation detection rate varied significantly (p=9.83×10-5) by untreated total cholesterol (TC) levels (25% in those <8.1mmol/l and 74% in those >10.0mmol/l), and by triglyceride levels (20% in those >2.16mmol/l and 60% in those <1.0mmol/l (p=0.0005)), with both effects confirmed in the replication sample (p for trend=0.0001 and p=1.8×10-6 respectively). There was no difference in the specificity or sensitivity of the SB criteria versus the Dutch Lipid Clinic Network score in identifying mutation carriers (AROC respectively 0.73 and 0.72, p=0.68). Conclusions: In this genetically heterogeneous cohort of FH patients the mutation detection rate was significantly dependent on pre-treatment TC and triglyceride levels. © 2013 The Authors