Atul Upadhyay

Antioxidant, antliglycation and antimicrobial activities of Ziziphus oxyphylla and Cedrela serrata extracts.

Aims: To determine the antioxidant, antiglycation and antibacterial activity of two selected plants found wild in Pakistan (Ziziphus oxyphylla and Cedrela serrata). Study Design: In vitro assessment of antioxidant assays, phenolic and flavonoid content, protein-glycation inhibition and antibacterial study. Place and Duration of Study: Department of Pharmaceutical Sciences, University of Antwerp Belgium (February April 2013; Antioxidant, Protein glycation). Department of Pharmacognosy, University of Karachi, Pakistan (March – June, 2012; antibacterial). Methodology: In vitro laboratory experimental tests; preparation of plant extracts, antioxidant assays (ABTS, PMS-NADH radicals), total phenol, total flavonoid; protein glycation (fluorescence); susceptibility tests (zones of inhibition). Results: The bark of C. serrata contained the highest amount of total phenol (0.35 ± 0.04 mg GAE/g extract) and exhibited significantly superior ABTS and PMS superoxide radical scavenging activity with IC50 values of 0.043 ± 0.001 mg/ml and 0.18 ± 0.01 mg/ml, respectively (P=0.05). Similarly, the protein-glycation assay revealed that the bark of C. serrata had the best inhibitory property with a low IC50 value of 0.61 ± 0.02 mg/ml Research Article European Journal of Medicinal Plants, 3(4): 520-529, 2013 521 (P=0.05), probably due to the presence of high amounts of total phenol. Furthermore, the various extracts showed considerable inhibition against both Gram–positive and – negative bacterial growth when compared against two standard drugs neomycin and doxycycline. Conclusion: The results of this study substantiate a probable role for these plants to be utilized as a natural source of antioxidant having a wide range of bioactivities.

Phytochemical and Pharmacological Investigations on Nymphoides indica Leaf Extracts

Nymphoides indica (L.) Kuntze (Menyanthaceae) is traditionally used in the Indian subcontinent. However, scientific data reporting its constituents are poor. This study aimed at evaluating its phytochemical constituents and various biological activities. Phytochemical investigations of the extracts and fractions resulted in the isolation of 5 lipophilic compounds, i.e. azelaic (nonanedioic) acid (1) and 4‐methyl‐heptanedioic acid (3), hexadecanoic (2) and stearic acid (5) and the fatty alcohol hexadecanol (4); 3 seco‐iridoids, i.e. 7‐epiexaltoside (6), 6″,7″‐dihydro‐7‐epiexaltoside (7) and menthiafolin (8); 3 flavonoids, i.e. 3,7‐di‐O‐methylquercetin‐4′‐O‐β‐glucoside (9), 3‐O‐methylquercetin‐7‐O‐β‐glucoside (10) and 3,7‐di‐O‐methylquercetin (11); scopoletin (12) and ferulic acid (13); and the monoterpenoids foliamenthoic acid (14) and 6,7‐dihydrofoliamenthoic acid methyl ester (15). Compounds 1–5 showed moderate antimicrobial activities, whereas compound 9 presented mild antiprotozoal activities against Trypanosoma brucei (IC50 8 μM), Leishmania infantum (IC50 32 μM) and Trypanosoma cruzi (IC50 30 μM). Antiglycation activity was shown by compounds 7 (IC50 0.36 mM), 10 (IC50 0.42 mM) and 15 (IC50 0.61 mM). Finally α‐glucosidase inhibition was shown by compounds 7, 9, 11 and 13–15. It could be concluded that N. indica leaf extracts possess mild to moderate antimicrobial, antiprotozoal, antioxidant and antidiabetic activities. Copyright

Antioxidant and Antiglycating Constituents from Leaves of Ziziphus oxyphylla and Cedrela serrata

Ziziphus oxyphylla and Cedrela Serrata plants have a folkloric use in Pakistan for treatments of different ailments, i.e., Jaundice, Hepatitis, Diabetes, and antimicrobial. Until now, none of the research studies have reported any phytochemical work on leaves of these two plants. This study aimed to isolate and perform phytochemical analysis in order to search for the constituent having the active role in treatment of the aforementioned ailments. A bioassay-guided fractionation and isolation procedure was used to isolate the concerned phytochemicals present in leaf extracts of Z. oxyphylla and C. serrata. The process involved the hyphenated techniques, i.e., Flash Chromatography, Semi-Preparative HPLC/DAD, UPLC/MS, and NMR in order to isolate and elucidate the structure of the phytochemicals. Seven compounds (1–7) were isolated and identified as flavonoids, more in particular glycosides of quercetin and kaempferol. They showed DPPH scavenging activity, compound 3 (isoquercitrin) being the most active one with an IC50 of 10.8 µg/mL (positive control quercetin; IC50 3.6 µg/mL). The superoxide-radical scavenging and total antioxidant (ABTS) assays indicated IC50 values ranging from 200 to 910 µg/mL and 170 to 320 µg/mL, respectively (positive control quercetin: 374 and 180 µg/mL, respectively). Furthermore, these compounds had low IC50 values for inhibition of protein glycation (AGEs inhibition), ranging from 530 to 818 µg/mL, comparable to aminoguanidine (510 µg/mL) used as a positive control. This study resulted in the identification of seven flavonoid glycosides for the first time from the leaves of Z. oxyphylla and C. serrata with antioxidative and antiglycating activities.

Kavalactones, a novel class of protein glycation and lipid peroxidation inhibitors.

Both advanced glycation endproducts and advanced lipoxidation endproducts are implicated in many age-related chronic diseases and in protein ageing. In this study, kawain, methysticin, and dihydromethysticin, all belonging to the group of kavalactones, were identified as advanced glycation endproduct inhibitors. With IC50 values of 43.5 ± 1.2 µM and 45.0 ± 1.3 µM for kawain and methysticin, respectively, the compounds inhibited the in vitro protein glycation significantly better than aminoguanidine (IC50 = 231.0 ± 11.5 µM; p = 0.01), an established reference compound. Kawain and methysticin also inhibited the formation of dicarbonyl compounds, which are intermediates in the process of advanced glycation endproduct formation. Similarly, kawain and aminoguanidine prevented the formation of thiobarbituric reactive substances in both low-density lipoprotein and linoleic acid oxidation. Moreover, kawain and aminoguanidine prevented advanced glycation endproduct formation by chelating Fe(3+) and Cu(2+) two to three times better than aminoguanidine. Furthermore, kawain increased the mean life span of Caenorhabditis elegans exposed to high glucose. With glycation inhibiting, lipid peroxidation inhibiting, metal chelating properties, and life span extending ability, kavalactones show a high potential as advanced glycation endproducts and advanced lipoxidation endproduct inhibitors.