Four types of crude extracts were obtained from the stem bark of Garcinia mangostana from which six xanthone derivatives: α-mangostin, β-mangostin, garcinone D, mangostenol, fuscaxanthone C and dulcisxanthone F were isolated. The structures of these compounds were elucidated and determined using spectroscopic techniques such as MS, 1D and 2D NMR. The in vitro anti-Bacillus assay was performed using the crude extracts as well as α-mangostin and β-mangostin against four Bacillus species; B. subtilis ATCC 6633, B. cereus ATCC 33019, B. megaterium ATCC 14581 and B. pumilus ATCC 14884. The ethyl acetate extract showed strong inhibitory activity against B. subtilis, B. cereus, B. megaterium and B. pumilus in disc diffusion assay with 10.33 ± 0.44 mm, 10.33 ± 0.44 mm, 9.00 ± 0.00 mm and 11.33 ± 0.17 mm inhibition zones, respectively. Nitric oxide inhibition activities indicated that two major compounds (α-mangostin, β-mangostin) exhibited very significant activity in the inhibition of LPS/IFN-γ stimulated RAW 264.7 macrophages with IC50 values of 29.81 ± 0.77 and 11.72 ± 1.16 μM, respectively. The chloroform and ethyl acetate extract of G. mangostana showed very potent activities.
Neptunia oleracea Lour. is a tropical plant cultivated in Southeast Asia. It is consumed as vegetable and traditional herb for the treatment of several disorders. The objective of the present work was to isolate the phenolic compounds from N. oleracea, followed by their bioactivity evaluation and quantitative analysis. The ethyl acetate (EtOAc) and methanol (MeOH) fractions of N. oleracea were subjected to various chromatographic techniques to isolate the phenolic compounds. The isolated phenolic compounds were characterised by several spectroscopic methods, including mass spectrometry (MS) and nuclear magnetic resonance (NMR). Then, these compounds were subjected to DPPH free radical scavenging as α-glucosidase inhibitory assays for the evaluation of their activities. Their contents in the fractions were analysed via high performance liquid chromatography (HPLC) quantitative analysis. Five phenolic compounds including quercetin-3-O-β-D-xylopyranoside (1), quercetin-3-O-α-Larabinopyranoside (2), quercetin-3-O-α-L-rhamnoside (3), methylgallate (4) and rutin (5) were isolated from N. oleracea for the first time. Evaluation on the DPPH free radical scavenging and α-glucosidase inhibitory activities of these compounds showed that methylgallate (4) was the most potent antioxidant and α-glucosidase inhibitors among them, with IC50 values of 17.25 and 50.76 μM, respectively. The HPLC quantitative analysis revealed the high content of the quercetin derivatives (compounds 1, 2 and 3) in the EtOAc fraction (ranging from 125.68 to 157.55 μg/mg) and methylgallate (4) in the MeOH fraction (75.25 μg/mg). Comparison of the bioactivities of the isolated phenolic compounds with the fractions indicated their significant contribution for the DPPH free radical scavenging of N. oleracea; while they might be working synergistically for the α-glucosidase inhibitory activity. The results of the present work could help to validate the contribution of phenolic compounds for the studied bioactivities of N. oleracea.
The aim of the present work was to compare and choose the best method to extract incurred
pesticide residues from green tea. Accelerated solvent extraction (ASE) with in-cell cleanup
and the quick, easy, cheap, effective rugged and safe (QuEChERS) methods were tested on
green tea samples with incurred beta-endosulfan pesticide. The extracts were analyzed by
GC-MS/MS and the recovery and the precision of both methods were compared. The average
recovery using ASE with the in-cell cleanup method was in the range of 89 to 92% which is
better than that obtained using a QuEChERS method. Both the ASE with in-cell cleanup and
the QuEChERS methods provided good precision with RSDs in the range of 12 to 15% and
17 to 18%, respectively. This finding indicates that the ASE method with the in-cell cleanup is
more suitable for the accurate determination of pesticides incurred in tea.
Momordica charantia, also known as bitter melon or ‘peria katak’ in Malaysia, is a member of the family Cucurbitaceae. Bitter melon is an excellent source of vitamins and minerals that made it extensively nutritious. Moreover, the seed, fruit and leave of the plant contain bioactive compounds with a wide range of biological activities that have been used in traditional medicines in the treatment of several diseases, including inflammation, infections, obesity and diabetes. The aim of this study was to evaluate changes in urinary metabolite profile of the normal, streptozotocin-induced type 1 diabetes and M. charantia treated diabetic rats using proton nuclear magnetic resonance (1H-NMR) -based metabolomics profiling. Study had been carried out by inducing diabetes in the rats through injection of streptozotocin, which exhibited type 1 diabetes. M. charantia extract (100 and 200 mg/kg body weight) was administrated to the streptozotocin-induced diabetic rats for one week. Blood glucose level after administration was measured to examine hypoglycemic effect of the extract. The results obtained indicated that M. charantia was effective in lowering blood glucose level of the diabetic rats. The loading plot of Partial Least Square (PLS) component 1 showed that diabetic rats had increased levels of lactate and glucose in urine whereas normal and the extract treated diabetic rats had higher levels of succinate, creatine, creatinine, urea and phenylacetylglycine in urine. While the loading plot of PLS component 2 showed a higher levels of succinate, citrate, creatine, creatinine, sugars, and hippurate in urine of normal rat compared to the extract treated diabetic rat. Administration of M. charantia extract was found to be able to regulate the altered metabolic processes. Thus, it could be potentially used to treat the diabetic patients.