New sesquiterpene and flavone arabinofuranoside derivative from the leaves of Fissistigma bicolor.

A new muurolane-type sesquiterpene, a new flavone arabinofuranoside derivative, and other five known flavone arabinofuranoside derivatives were isolated from the leaves of Fissistigma bicolor (Annonaceae family). Their chemical structures were determined to be (1S,6R,7S)-muurola-4,10(14)-diene-15-ol (1), quercetin 3-O-ß-D-apiofuranosyl-(1→2)-α-L-arabinofuranoside (2), quercetin 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinofuranoside (3), quercetin 3-O-α-L-arabinofuranoside (4), kaempferol 3-O-ß-D-apiofuranosyl-(1→2)-α-L-arabinofuranoside (5), kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinofuranoside (6), and kaempferol 3-O-α-L-arabinofuranoside (7) by analyses of HR-ESI-MS and NMR spectral data. Compounds 4 and 7 containing monosaccharide, arabinofuranoside, potentially inhibited NO productions in LPS activated RAW264.7 cells (IC50 13.4 ± 0.5 and 12.6 ± 0.4 µM) in compared to disaccharide derivatives (IC50 ranging from 58.9 ± 3.3 to 65.6 ± 3.8 µM).

Cannadicas A and B: two new oligosaccharide esters from the roots of Canna indica L.

Two new sucrose derivatives, named as cannadica A (1) and cannadica B (2), and eight known compounds, 6'-O-acetyl-3-O-(E)-p-coumaroylsucrose (3), heterophylloside C (4), 6'-O-vanilloylarbutin (5), isotachioside (6), 2,6-dimethoxy-p-hydroquinone 1-O-ß-D-glucopyranoside (7), 3,5-dimethoxy-p-hydroquinone 1-O-ß-D-glucopyranoside (8), benzyl glucoside (9), and 3,4-dihydroxybenzaldehyde (10) were isolated from the roots of Canna indica L. by various chromatographic methods. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS and NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-10 were evaluated their antioxidant activity by peroxyl radical absorbance capacity assay. Compounds 4 and 5 exhibited the most peroxyl radical absorbance capacity. At concentration of 1 µM, their ORACROO* values were 4.86 ± 0.39 and 3.11 ± 0.26, respectively, fold-up to that of trolox as an internal standard.

Screening of Endophytic Bacteria Isolated from Weed Plant to Biocontrol Stem Rot Disease on Pitaya (Hylocereus undatus)

Abstract Endophytic bacteria from weed are emerging as valuable alternatives for biochemical pesticides in sustainable agriculture. This study aims to discover the antagonistic effects of some endophytic bacteria isolated from weed (Lactuca indica) against A. alternata, a casual of stem end rot disease of pitaya. A total of 14 endophytic bacteria were isolated and four of them presented in vitro antagonistic activity against A. alternata. Of four, strain L115 significantly inhibited the pathogenic growth with a mean inhibition diameter of 12.67 ± 0.02 mm, while the other three (strain L110, L111, and L114) showed a weak inhibition. The results indicated that strain L115 could belong to the Bacillaceae family while the other three (strain L110, L111, and L114) had characteristics of the Pseudomonadaceae family. Interestingly, strain L115 showed positive results for phosphate solubilization, indole acetic acid (IAA), and biofilm production, whereas three other strains presented weak capabilities for phosphate solubilization, biofilm production and IAA production. In addition, the filtrate of strain L115 presented antifungal activity on biocontrol tests in vitro. Especially, strain L115 significantly increased seedling biomass of pitaya and tomato compared to the control. Hence, these results suggest strain L115 has the potential to be used as biocontrol agents against A. alternata. More studies should be done in the future to evaluate their efficiency in field conditions.

Prenylated flavonoids and other constituents from Macaranga indica.

Four new prenylated flavonoids, macarindicins I-IV (1-4) together with ten known compounds, broussoflavonol F (5), vedelianin (6), schweinfurthin E (7), vitexin (8), 2″-rhamnosyl vitexin (9), isovitexin (10), (6R,7E,9R)-9-hydroxy-megastigman-4,7-dien-3-one-9-O-ß-D-glucopyranoside (11), 6S,9R)-roseoside (12), (6S,9S)-roseoside (13), and bridelionoside B (14) were isolated from the leaves of Macaranga indica. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-, 2D-NMR, and MS data. All the isolated compounds were evaluated for their cytotoxic activities against four human cancer cell lines including KB, MCF-7, HepG-2, and LU. As a result, compound 6 significantly exhibited cytotoxic activity against all tested human cancer cell lines with IC50 values ranging from 4.7 to 11.0 µM. Compounds 2, 5, and 7 showed moderate cytotoxic activity with IC50 values ranging from 7.0 to 38.7 µM.

Pregnane glycosides from Gymnema inodorum and their α-glucosidase inhibitory activity.

Two new pregnane glycosides, gyminosides A and B (1 and 2) and three known, tinctoroside B (3), tinctoroside C (4), and gymnepregoside F (5) were isolated from the leaves of Gymnema inodorum (Lour.) Decne. Their structures were elucidated by physical and chemical methods and comparing with those reported in the literature. All these compounds were evaluated for α-glucosidase assay. Compound 5 exhibited the most anti α-glucosidase activity with inhibitory percentage of 63.7 ± 3.9% at the concentration of 200 µM. Compounds 1-4 showed moderate anti α-glucosidase activity with inhibitory percentage ranging from 40.0 to 52.1%.

Dihydrostilbene glycosides from Camellia sasanqua and their α-glucosidase and α-amylase inhibitory activities.

Using chromatographic methods, three new dihydrostilbene glycosides, sasastilbosides A-C (1-3) and four known compounds, catechin (4), rutin (5), nicotiflorin (6), and rehmaionoside A (7) have been isolated from Camellia sasanqua Thunb. Their chemical structures were elucidated by spectroscopic methods (1 D-, 2 D-NMR) and mass spectra. Compounds 1-7 were evaluated for α-glucosidase and α-amylase inhibitory effects. Compounds 3 and 4 showed α-glucosidase inhibitory activity with IC50 values of 77.6 ± 1.6 and 72.4 ± 1.3 µM, respectively. Compound 1 showed α-amylase inhibitory activity with IC50 value of 53.7 ± 1.6 µM.

Three new flavonol glycosides from Fissistigma pallens.

Three new flavonol glycosides, fissflavosides A-C (1-3), together with six known flavonol glycosides, kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-galactopyranoside (4), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-ß-D-galactopyranoside (5), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-ß-D-glucopyranoside (6), rhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (7), rutin (8), and isorhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-galactopyranoside (9) were isolated from the methanol extract of the Fissistigma pallens leaves. Their chemical structures were determined by 1D-, 2D-NMR, and MS data as well as in comparison with reported data in the literature. Compounds 1-9 showed weak cytotoxic activity on three human cancer cell lines, HT-29, A-2058, A-549 with IC50 ranging from 134.6 to 162.6 µM. In addition, the antioxidant capacities of compounds were also tested by ORAC assay. All compounds showed significant antioxidant with trolox equivalents ranging from 4.4 to 8.6 µM at the concentration of 1.0 µM. The results indicated 7 and 8 having meaningful reducing capacity of copper (I) ions of 2.7 to 6.9 µM at the concentrations of 1 and 2 µM.

Sample checklist of Gastropoda and Bivalvia in Cham Islands, Vietnam.

BACKGROUND: Cham Islands (Cu Lao Cham) is a group of 8 small islands in the Quang Nam province, Central Vietnam. There is only one study that mentioned the diversity of marine molluscs in this area. However, the data on species composition have not been digitised and not stored or shared for other purposes. Our paper aims to share the checklist of marine mollusc species (Bivalvia and Gastropoda) species that we collected from the littoral zone of Cham Islands in May 2017. This is the first digitised and online data of marine molluscs in Vietnam. It is very important for researchers in various fields such as the structure and function of ecology and biodiversity monitoring. NEW INFORMATION: This study provides a checklist of the marine bivalves and snails in the Cham Islands of Vietnam. Moreover, this first widely shared data of biodiversity in Vietnam can trigger biodiversity data papers in this data-poor country.The data of this study will be important inputs for better understanding biodiversity on the Cham Islands and Vietnam as well as for forming the basis for monitoring, exploitation and conservation of biodiversity in this area.In total, 145 taxa were recorded, 46 bivalve taxa and 99 snail taxa, from which 128 were identified to the species level and 17 were identified to the genus level. There are 116 new species records for the Cham Islands.The specimens are currently deposited in the Institute of Ecology and Biological Resources (IEBR), Vietnam Academy of Science and Technology (VAST).