Immunomodulatory potential of extracts, fractions and pure compounds from Phyllanthus amarus and Psidium guajava on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes.

This study aimed to identify major phytochemical constituents, as well as compare the immunomodulatory effects of Psidium guajava L. and Phyllanthus amarus Schun and Thonn crude ethanol extracts and their fractions on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes (HKLs). Moreover, pure constituents were also investigated for their effects on those cells: hypophyllanthin, identified as a major constituent of P. amarus crude extracts and its hexane fraction; corosolic acid, ursolic acid, and oleanolic acid, identified in P. guajava crude extract, ethyl acetate and dichloromethane fractions; with other terpenic derivatives, as well as guajaverin and avicularin, identified with other flavonoids by LC-UV-MS in the crude P. guajava extract and its ethyl acetate fraction. Cell viability, respiratory burst assay (RBA), nitric oxide synthase (NOS) and lysozyme activity in HKLs were analyzed after 24 h stimulation with each extract (10, 20 and 40 µg/mL) or pure compound (7.5, 15 and 30 µM). Our results show that the hexane fraction of both plant extracts inhibited the viability of HKLs, while several other fractions enhanced the cell viability. All P. guajava fractions at all or some concentration considerably enhanced the RBA production in HKLs. Similarly, NOS production was also significantly increased by some or all concentrations of P. guajava dichloromethane and ethyl acetate fractions. However, the NOS production was dose-dependently inhibited in HKLs treated with Pa ethyl acetate and both plants aqueous fractions at 10 or 10 and 40 µg/mL respectively. The lysozyme activity in cells treated with P. guajava crude extracts and all its organic solvent fractions were stronger than those in P. amarus treatments. Pure compounds including corosolic acid, guajaverin, ursolic acid, hypophyllanthin inhibited the HKLs viability according to concentration and type of compound. All pure compounds except avicularin significantly stimulated, at certain or all concentrations, the RBA production and/or the lysozyme activity in HKLs. The NOS production was significantly reduced in HKLs treated with oleanolic acid (30 µM) and hypophyllanthin (7.5 µM) while its level was increased by hypophyllanthin at 30 µM. These results highlighted that the crude ethanol extracts of P. guajava and P. amarus, their fractions and some of their pure components at certain concentrations can potentially act as immunomodulators, and could be considered as valuable candidates in fishery sciences.

Isolation and purification of potential weed inhibitors from Mimosa pigra L.

The diversity in structure and herbicidal properties detected in natural phytotoxic compounds could bring about advantages for development bio-herbicides. The present study was carried out search for potential weed inhibitors from the parts of Mimosa pigra L. The ethyl acetate (EtOAc) extract of leaf of M. pigra showed inhibitory activity during the time that Echinochloa crus-galli (barnyardgrass) germinates and grows, which is greater than that of other extracts. From this active extract, potent growth inhibitors were isolated and identified by column chromatography (CC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (1H and 13C NMR). The six compounds were purified in this study namely: lupeol (C1, 13.2 mg), stigmastane-3,6-dione (C2, 14.7 mg), quercetin (C3, 20.2 mg), chrysoeriol (C4, 28 mg), methyl gallate (C5, 21.5 mg) and daucosterol (C6, 16.0 mg). The C2 (quercetin) compound completely inhibited the emergency, shoot height and root length of E. crus-galli at 1 mg/mL concentration (IC50 shoot height = 0.56 mg/mL). This was also the first study to report the isolation and allelopathic activity of lupeol, chrysoeriol and daucosterol from M. pigra leaf. Findings of this study highlighted that quercetin from M. pigra may become bio-herbicide to control barnyard grass and other grass weeds for the development of safe agriculture.

Three new iridoid glucoside salts from Hedyotis tenelliflora Growing in Vietnam.

Three new sodium salts of iridoid acids, deacetylasperulosidic acid sodium salt (1), teneoside D (2), and teneoside E (3) were isolated from the leaves of Hedyotis tenelliflora Blume (Rubiaceae), together with seven known iridoids, 6alpha-hydroxygeniposide (4), 6beta-hydroxygeniposide (5), 6-O-methyldeacetylasperulosidic acid methyl ester (6), 6-O-methylscandoside methyl ester (7), 6alpha-methoxygeniposidic acid (8), daphylloside (9), and mollugoside methyl ester (10). Their chemical structures were elucidated by 1D and 2D NMR spectroscopy, as well as HR-ESI-MS analysis.