Antimicrobial high molecular weight pectin polysaccharides production from diverse citrus peels using a novel PL10 family pectate lyase.

The discovery of environmentally friendly enzymes that can convert inexpensive and abundant citrus peel pectin into high value-added product is a potential avenue for the citrus peel application. In this study, a novel PL10-family pectate lyase (pelA) was characterized from marine bacterium Echinicola pacifica. PelA was a Ca2+ dependent pectate lyase whose activity was highest at pH 8 and 40 °C. It was capable of degrading polygalacturonic acid (PGA) and citrus peel pectin (CPP), but not apple peel pectin. Notably, PelA hydrolyzed PGA to high molecular weight polysaccharide (average molecular weight 111.4 kDa). Moreover, PelA was also able to degrade CPP from nine distinct citrus species into polysaccharides (average molecular weight ranging from 84.7 to 539.2 kDa) that showed antimicrobial activity against Staphylococcus epidermidis (88.8 %), Bacillus subtilis (99.8 %), Staphylococcus aureus (92.1 %), Escherichia coli (100.0 %) and Klebsiella pneumoniae (86.4 %). Considering the high market value of pectin in the food industry, PelA's capacity to convert citrus pectin into high molecular weight polysaccharides lays a foundation for its applications.

Antioxidant and anti-inflammatory activity of constituents isolated from Dendrobium nobile (Lindl.).

Dendrobium nobile (Lindl.) have long been used as herbal tea and a traditional herbal medicine to treat Alzheimer's disease (AD). In the current study, nineteen compounds (1-19), including two new vitamin E homologues (1-2), one new sesquiterpene (6), and two new dendrobines (7, 8), were isolated and identified from stems of Dendrobium nobile. Their structures were elucidated on the basis of NMR, 13C NMR calculation, and DP4+ probability analyses. The absolute configurations of new compounds were determined by electronic circular dichroism (ECD) data analysis. Antioxidant, anti-inflammatory, and cytotoxic activities of isolated compounds were evaluated. Among them, compound 2 demonstrated significant antioxidant activity compared with ascorbic acid (VC), while compounds 2 and 4 also exhibited an equal effect to positive control cisplatin. This study on the biological activity of the new vitamin E homologues from Dendrobium nobile may indicate its potential application in the pharmaceutical and food industries.

Photosensitizer doped zeolitic imidazolate framework-8 nanocomposites for combined antibacterial therapy to overcome methicillin-resistant Staphylococcus aureus (MRSA).

Antibiotics have played an important role in the treatment of bacteria related infections. However, the rapid emergence of multidrug-resistant bacteria and limited number of antibiotics available is a great challenge to humankind. To address this problem, we are proposing a photosensitizer-modified biodegradable zeolitic imidazolate framework-8 nanocomposite that can kill not only Gram-positive bacteria Staphylococcus aureus, but also methicillin-resistant Staphylococcus aureus (MRSA) with high efficacy. In vivo testing revealed that these nanocomposites are highly effective for in vivo wound disinfection with minimal side-effects. In conclusion, this photosensitizer-modified biodegradable nanocomposite could be very promising for a synergistic antibacterial therapy to overcome MRSA.