Anti-osteoclastogenic cycloartane saponins from Mussaenda pubescens.

The methanolic extract of Mussaenda pubescens Dryand leaves exhibited significant anti-osteoclastogenic activity. Chemical investigation of M. pubescens led to the isolation of one new cycloartane saponin, mussaendoside X (1) along with eight known compounds: heinsiagenin A 3-O-[α-L-rhamnopyranosyl-(1→2)-O-ß-D-glucopyranosyl-(1→2)]-O-ß-D-glucopyranoside (2), mussaendoside O (3), heinsiagenin A 3-O-[α-L-rhamnopyranosyl-(1→2)-O-ß-D-glucopyranosyl-(1→2)]-O-ß-D-glucopyranosyl-(1→4)-O-ß-D-glucopyranoside (4), mussaendoside G (5), mussaendoside U (6), shanzhiside methyl ester (7), barlerin (8) and musaenoside (9). Their structures were elucidated by extensive spectroscopic methods including 1D- and 2D-NMR as well as MS analysis and comparison with the literature. Cycloartane saponins 1-6 positively suppressed osteoclast formation in an anti-osteoclastogenic screening assay. Consequently, treatment of RANKL-stimulated RAW 264.7 cells with compounds 1-4 significantly decreased the number of osteoclasts in a concentration-dependent manner. Six compounds from M. pubescens, with the new cycloartane, mussaendoside X, were shown for the first time as potential effective inhibitors of osteoclastogenesis.

Impact of aluminum chloride on process performance and microbial community structure of granular sludge in an upflow anaerobic sludge blanket reactor for natural rubber processing wastewater treatment.

In this study, granular sludge formation was carried out using an aluminum chloride supplement in an upflow anaerobic sludge blanket (UASB) reactor treating natural rubber processing wastewater. Results show that during the first 75 days after the start-up of the UASB reactor with an organic loading rate (OLR) of 2.65 kg-COD·m(-3)·day(-1), it performed stably with a removal of 90% of the total chemical oxygen demand (COD) and sludge still remained in small dispersed flocs. However, after aluminum chloride was added at a concentration of 300 mg·L(-1) and the OLR range was increased up to 5.32 kg-COD·m(-3)·day(-1), the total COD removal efficiency rose to 96.5 ± 2.6%, with a methane recovery rate of 84.9 ± 13.4%, and the flocs began to form granules. Massively parallel 16S rRNA gene sequencing of the sludge retained in the UASB reactor showed that total sequence reads of Methanosaeta sp. and Methanosarcina sp., reported to be the key organisms for granulation, increased after 311 days of operation. This indicates that the microbial community structure of the retained sludge in the UASB reactor at the end of the experiment gave a good account of itself in not only COD removal, but also granule formation.