Effect of Extraction Techniques on Phytochemicals and Antioxidants Activity of Garcinia quaesita Leaves

Garcinia quaesita is an endemic plant in Sri Lanka with a wide array of domestic and medicinal values, yet very limited studies have been reported. The goal of this study was to investigate the phytochemicals and antioxidants capacity of leaves of G. quaesita under different extraction techniques in order to monitor the effect of extraction techniques on the above parameters. Water was used as the solvent and four extraction methods, namely sonication (EN01, one-hour,RT, 40 kHz), Soxhlet (EN02, six-hours, 105 ºC), maceration with agitation (EN03, six-hours, RT, 1000 rpm), and maceration with agitation upon heating (EN04, six-hours, 60 ºC, 1000 rpm), were applied. Phytochemical screenings and quantification of polyphenolics (TPC), flavonoids (TFC), tannins (TTC), terpenoids (TC), saponins (SC), and alkaloids (AC) were performed using standard methods, whereas antioxidants capacity was assessed using FRAP and DPPH assays. The results revealed that G. quaesita contains a wide range of phytochemicals and the TPC, TTC and SC profiles appeared to be higher in the extraction process of EN04 (60.73 ± 0.06 mg GAE/g, 60.12 ± 0.06 mg TAE/g, and 257.64 ± 0.72 mg SE/g, respectively) whereas those were lower in the technique EN01. In addition, TFC and TC levels were high in EN02 (3.02 ± 0.00 mg QE/g and 17.75 ± 0.04 mM LE/g respectively) and besides, TFC was low in method EN03, whereas TC was low in EN01. Interestingly, AC was found to be higher in EN03 (1.16 ± 0.03 mg AE/g) and lesser in EN02. Total antioxidant capacity ( FRAP value) was calculated to be higher in extraction method EN04 (72.08 ± 0.00 mg Trolox Eq/g) whereas it was lower in extraction method EN01. The method, EN03 gave the lower IC50 value in DPPH radical scavenging assay (10.49 ± 0.12 mg/ml), indicating high scavenging activity. In conclusion, the extraction technique EN04 is well suitable to extract polyphenolics and antioxidants from G. quaesita leaves. Though G. quaesita leaves contain a diverse range of bioactive compounds and antioxidants properties, it is important to choose the correct extraction technique based on the objectives of the desired research work, as the number of phytochemicals extracted, and antioxidant capacity varies depending on the extraction technique used. Full paper submission of ICIET 202

Phytochemistry and medicinal properties of Psidium guajava L. leaves: A review

Psidium guajava L. (Myrtaceae), also known as guava, is a medicinal tree native to tropical America that has been introduced and is widely available in many countries. Almost all plant parts of P. guajava have a long history of being used to treat a variety of ailments, in addition to applications as foods. Guava leaves are used as both medicine and food purposes, and there are numerous scientific reports on their medicinal uses, chemical composition and pharmacological properties. Cancer, blood pressure, diarrhea, bowel irregularities, diabetes, cough, cold, constipation, dysentery, scurvy, weight loss, improves skins tonicity are some of the diseases treated with guava leaves. Polyphenols, flavonoids, saponins, tannins, terpenoids, glycosides, flavones, cardiac glycosides, cardenolides, phlobatanins, steroids and other classes of bioactive compounds have been identified from the leaves. The primary chemical constituents of guava leaves are phenolic compounds, iso-flavonoids, gallic acid, catechin, quercetin, epicathechin, rutin, naringenin, kaempferol, caryophyllene oxide, p-selinene etc. Several studies have demonstrated its pharmacological activities including antioxidant, antimicrobial, antidiabetic, antitumor, anticancer, antidiarrheal, healing, cytotoxic, hepatoprotective, anti-inflammatory, antimalarial/ anti-plasmodial, dental plaque, antiglycative and many more. This review is aimed on compiling all the literature reported on pharmacological activities and phytochemical compositions of guava leaves as a support to the scientific community for further studies and to provide scientific data to validate its traditional uses

A novel estrogen-regulated avian apolipoprotein.

In search for yet uncharacterized proteins involved in lipid metabolism of the chicken, we have isolated a hitherto unknown protein from the serum lipoprotein fraction with a buoyant density of ≤1.063 g/ml. Data obtained by protein microsequencing and molecular cloning of cDNA defined a 537 bp cDNA encoding a precursor molecule of 178 residues. As determined by SDS-PAGE, the major circulating form of the protein, which we designate apolipoprotein-VLDL-IV (Apo-IV), has an apparent Mr of approximately 17 kDa. Northern Blot analysis of different tissues of laying hens revealed Apo-IV expression mainly in the liver and small intestine, compatible with an involvement of the protein in lipoprotein metabolism. To further investigate the biology of Apo-IV, we raised an antibody against a GST-Apo-IV fusion protein, which allowed the detection of the 17-kDa protein in rooster plasma, whereas in laying hens it was detectable only in the isolated ≤1.063 g/ml density lipoprotein fraction. Interestingly, estrogen treatment of roosters caused a reduction of Apo-IV in the liver and in the circulation to levels similar to those in mature hens. Furthermore, the antibody crossreacted with a 17-kDa protein in quail plasma, indicating conservation of Apo-IV in avian species. In search for mammalian counterparts of Apo-IV, alignment of the sequence of the novel chicken protein with those of different mammalian apolipoproteins revealed stretches with limited similarity to regions of ApoC-IV and possibly with ApoE from various mammalian species. These data suggest that Apo-IV is a newly identified avian apolipoprotein

D25V apolipoprotein C-III variant causes dominant hereditary systemic amyloidosis and confers cardiovascular protective lipoprotein profile

Apolipoprotein C-III deficiency provides cardiovascular protection, but apolipoprotein C-III is not known to be associated with human amyloidosis. Here we report a form of amyloidosis characterized by renal insufficiency caused by a new apolipoprotein C-III variant, D25V. Despite their uremic state, the D25V-carriers exhibit low triglyceride (TG) and apolipoprotein C-III levels, and low very-low-density lipoprotein (VLDL)/high high-density lipoprotein (HDL) profile. Amyloid fibrils comprise the D25V-variant only, showing that wild-type apolipoprotein C-III does not contribute to amyloid deposition in vivo. The mutation profoundly impacts helical structure stability of D25V-variant, which is remarkably fibrillogenic under physiological conditions in vitro producing typical amyloid fibrils in its lipid-free form. D25V apolipoprotein C-III is a new human amyloidogenic protein and the first conferring cardioprotection even in the unfavourable context of renal failure, extending the evidence for an important cardiovascular protective role of apolipoprotein C-III deficiency. Thus, fibrate therapy, which reduces hepatic APOC3 transcription, may delay amyloid deposition in affected patients

Apolipoprotein CIII structure and dynamics by NMR spectroscopy : residual dipolar couplings for detergent solubilized proteins

Contains fulltext : mmubn000001_481082751.pdf (publisher's version ) (Closed access)Radboud Universiteit Nijmegen, 7 januari 2008Promotor : Wijmenga, S.S.178 p

Structural basis of molecular recognition of the Leishmania Small Hydrophilic Endoplasmic Reticulum-associated Protein (SHERP) at membrane surfaces

The 57-residue small hydrophilic endoplasmic reticulum-associated protein (SHERP) shows highly specific, stage-regulated expression in the non-replicative vector-transmitted stages of the kinetoplastid parasite, Leishmania major, the causative agent of human cutaneous leishmaniasis. Previous studies have demonstrated that SHERP localizes as a peripheral membrane protein on the cytosolic face of the endoplasmic reticulum and on outer mitochondrial membranes, whereas its high copy number suggests a critical function in vivo. However, the absence of defined domains or identifiable orthologues, together with lack of a clear phenotype in transgenic parasites lacking SHERP, has limited functional understanding of this protein. Here, we use a combination of biophysical and biochemical methods to demonstrate that SHERP can be induced to adopt a globular fold in the presence of anionic lipids or SDS. Cross-linking and binding studies suggest that SHERP has the potential to form a complex with the vacuolar type H+-ATPase. Taken together, these results suggest that SHERP may function in modulating cellular processes related to membrane organization and/or acidification during vector transmission of infective Leishmania

LPL gene variants affect apoC-III response to combination therapy of statins and fenofibric acid in a randomized clinical trial of individuals with mixed dyslipidemia

ApoC-III is a proatherogenic protein associated with elevated triglycerides; its deficiency is associated with reduced atherosclerosis. Mixed dyslipidemia, characterized by elevated triglyceride and apoC-III levels and low HDL cholesterol level, with or without elevated LDL cholesterol, increases cardiovascular disease risk and is commonly treated with combined statin and fibrate therapy. We sought to identify single nucleotide polymorphisms (SNPs) associated with apoC-III level response to combination therapy with statins and fenofibric acid (FA) in individuals with mixed dyslipidemia. Participants (n = 1,250) in a multicenter, randomized, double-blind, active-controlled study examining response to FA alone and in combination with statin were genotyped for candidate SNPs. Multivariate linear regression and two-way ANOVA for percent change in apoC-III level were performed. SNPs in the lipoprotein lipase (LPL) gene region, rs1801177 (P = 4.7 × 10(−8)), rs7016529 (P = 1.2 × 10(−6)), and rs249 (P = 4.1 × 10(−5)), were associated with apoC-III response to combination therapy. A haplotype composed of the minor alleles of these SNPs, with 2% population frequency, was associated with an unexpected apoC-III increase in response to statins and FA. This is the first report to show that genetic variation within the LPL gene region can affect the response of apoC-III levels to combined statin and FA therapy