Penthorum chinense Pursh leaf tea debittering mechanisms via green tea manufacturing process and its influence on NAFLD-alleviation activities.

The green-tea manufacturing process showed good effect of flavor improving, debittering and shaping in making Penthorum chinensePursh leaf (PL) tea (PLT), which serves as a polyphenol dietary supplement and beverage raw material. GC-MS results showed that its unpleasant grassy odor decreased by 42.8% due to dodecanal, geranylacetone, and (E)-2-nonenal reduction, coupled with 1-hexadecanol increasing. UPLC-ESI-TOF-MS identified 95 compounds and showed that the debittering effect of green-tea manufacturing process was attributed to decreasing of flavonols and lignans, especially quercetins, kaempferols and luteolins, and increasing of dihydrochalcones which act as sweeteners bitterness-masking agents, while astringency was weakened by reducing delphinidin-3,5-O-diglucoside chloride, kaempferol-7-O-ß-d-glucopyranoside, and tannins. The increase of pinocembrins and catechins in aqueous extracts of PLT, maintained its hepatoprotective, NAFLD-alleviation, and hepatofibrosis-prevention activities similar to PL in high fat-diet C57BL/6 mice, with flavonoids, tannins, tannic acids, and some newfound chemicals, including norbergenin, gomisin K2, pseudolaric acid B, tanshinol B, as functional ingredients.

Premna microphylla Turcz leaf pectin exhibited antioxidant and anti-inflammatory activities in LPS-stimulated RAW 264.7 macrophages.

Premna microphylla turcz leaf juice with polysaccharides (PMPs) as its main component, are raw material of jelly-like Chinese traditional food "Guanyin tofu", which were also experiencedly used to relieve inflammation-related symptoms. Here three kinds of PMPs were extracted in alkaline (APMP), water (WPMP) and acidic (HPMP) conditions, being characteristic of RG I, high- and low-methoxyl HG pectin, respectively, in amorphous form with diverse surface microstructures, among which APMP predominantly composed of Glucose instead of galacturonic acid, showing wider molecular weight distribution and more branched chains. PMPs showed remarkable radical scavenging capability, and especially APMP at concentrations above 50 µg/mL effectively inhibited the reactive oxygen species and malondialdehyde production in LPS-stimulated RAW 264.7 macrophages, by enhancing enzymatic activities of endogenous superoxide dismutase, glutathione peroxidase and catalase, and accordingly alleviated inflammatory cytokines. Thus, PMPs could be promising non-toxic natural dietary supplement to improve chronic inflammation-induced diseases.

Study on the antibacterial activities of emodin derivatives against clinical drug-resistant bacterial strains and their interaction with proteins.

BACKGROUND: Novel haloemodin (HEI2) synthesized by modifying emodin, a traditional Chinese medicine component, possesses remarkable antibacterial activity, being much more effective than its parent nucleus, emodin. METHODS: Firstly, we discovered that HEI2 increases bacterial cell membrane permeability to potassium ions more drastically than emodin. We thus further investigated the interaction of haloemodin and protein using a fluorescence quenching and circular dichroism (CD) study based on bovine serum albumin (BSA). RESULTS: HEI2 spontaneously bound to BSA at Trp 212 residue (subdomain IIA) by hydrogen bonds and van der Waals interactions to forms HEI2-BSA complexes, and this binding decreased the α-helical content of BSA. We also confirmed that emodin bound to BSA by hydrophobic interaction alone. CONCLUSIONS: These results suggest that the main responses for the substantial antibacterial activities of HEI2 are a disruption of the bacterial plasma membrane function and the interaction with biological functional proteins. Furthermore, the study of the interaction of drugs with BSA, which has a fluorescent group tryptophan residue similar to many bio-functional proteins, will be a simple and inexpensive scope-reducing method in screening new drugs.

Haloemodin as novel antibacterial agent inhibiting DNA gyrase and bacterial topoisomerase I.

Drug-resistant bacterial infections and lack of available antibacterial agents in clinical practice are becoming serious risks to public health. We synthesized a new class of haloemodins by modifying a traditional Chinese medicine component, emodin. The novel haloemodin exerts strong inhibitory activity on bacterial topoisomerase I and DNA gyrase, and not on the topoisomerases of human origin. In principle, it shows remarkable antibacterial activities against laboratory and clinically isolated Gram-positive bacteria, including vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus. We further expanded its antibacterial spectrum into against Gram-negative bacteria with the assistance of polymyxin B nonapeptide, which helps haloemodin to penetrate through the bacterial outer membrane. Finally, the therapeutic effect of haloemodin in vivo was confirmed in curing S. aureus-induced keratitis on rabbit model. With distinctive structural difference from the antibiotics we used, the haloemodins are of value as promising antibacterial pharmacophore, especially for combat the infections caused by drug-resistant pathogens.