Context:Lentinus squarrosulus Mont. (Polyporaceae) is an interesting source of diverse bioactive compounds.Objective: This is the first study of the anticancer activity and underlying mechanism of peptides extracted from Lentinus squarrosuls.Materials and methods: Peptides were isolated from the aqueous extract of L. squarrosulus by employing solid ammonium sulphate precipitation. They were further purified by ion-exchange chromatography on diethylaminoethanol (DEAE)-cellulose and gel filtration chromatography on Sephadex G25. Anticancer activity was investigated in human lung cancer H460, H292 and H23 cells cultured with 0–40 μg/mL of peptide extracts for 24 h. Cell viability and mode of cell death were evaluated by MTT and nuclear staining assay, respectively. Western blotting was used to investigate the alteration of apoptosis-regulating proteins in lung cancer cells treated with peptide extracts (0–20 μg/mL) for 24 h.Results: The cytotoxicity of partially-purified peptide extracts from L. squarrosulus was indicated with IC50 of ∼26.84 ± 2.84, 2.80 ± 2.14 and 18.84 ± 0.30 μg/mL in lung cancer H460, H292 and H23 cells, respectively. The extracts at 20 μg/mL induced apoptosis through the reduction of anti-apoptotic Bcl-2 protein (∼0.5-fold reduction) and up-regulation of BAX (∼4.5-fold induction), a pro-apoptotic protein. Furthermore, L. squarrosulus peptide extracts (20 μg/mL) also decreased the cellular level of death receptor inhibitor c-FLIP (∼0.6-fold reduction).Conclusions and discussion: This study provides the novel anticancer activity and mechanism of L. squarrosulus peptide extracts, which encourage further investigation and development of the extracts for anticancer use.

A citrate synthase (CS) deletion mutant of Agrobacterium tumefaciens C58 is highly attenuated in virulence. The identity of the mutant was initially determined from its amino acid sequence, which is 68% identical to Escherichia coli and 77% identical to Brucella melitensis. The mutant lost all CS enzymatic activity, and a cloned CS gene complemented a CS mutation in Sinorhizobium. The CS mutation resulted in a 10-fold reduction in vir gene expression, which likely accounts for the attenuated virulence. When a plasmid containing a constitutive virG [virG(Con)] locus was introduced into this mutant, the level of vir gene induction was restored to nearly wild-type level. Further, the virG(Con)-complemented CS mutant strain induced tumors that were similar in size and number to those induced by the parental strain. The CS mutation resulted in only a minor reduction in growth rate in a glucose-salts medium. Both the CS mutant and the virG(Con)-complemented CS strain displayed similar growth deficiencies in a glucose-salts medium, indicating that the reduced growth rate of the CS mutant could not be responsible for the attenuated virulence. A search of the genome of A. tumefaciens C58 revealed four proteins, encoded on different replicons, with conserved CS motifs. However, only the locus that when mutated resulted in an attenuated phenotype has CS activity. Mutations in the other three loci did not result in attenuated virulence and any loss of CS activity, and none were able to complement the CS mutation in Sinorhizobium. The function of these loci remains unknown.

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Aims:To isolate and characterize an antimicrobial peptide from fruiting bodies of Lentinus squarrosulus Mont., the Thai common edible mushroom. Methodology and results: Solid ammonium sulfate at 40-80% (w/v) final concentration was utilized to precipitate the proteins and further purified by ion exchange chromatography on DEAE-cellulose and gel filtration chromatography on Sephadex G-25. The peptide was adsorbed on DEAE-cellulose and Sephadex G-25. It appeared as a single band with a molecular mass of about 17 kDa (kilodalton) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Further investigation of antimicrobial properties of purified peptide revealed that it has no activity against both Gram positive and Gram negative bacteria. However, it exhibited strong antifungal activity against various species of fungal pathogen of human. Among the high sensitive strains, Trichophyton mentagrophytes, T. rubrum, and Candida tropicalis are clinical isolates. Moreover, the potency was found to be concentration dependent and comparable with Ketoconazole, the commercial antifungal drug. Conclusion, significance and impact study: In this work, the novel bioactive peptide from fruiting bodies of L. squarrosulus Mont. has been isolated. It shows potent activity against various clinical isolates of fungal pathogen of human. It may have potential for pharmaceutical application.

Methanolic extracts from the seed coats of five major tamarinds (Srichomphu, Sithong‐nak, Sithong‐bao, Priao‐yak and Khanti) cultivated in Thailand were investigated for their content of phenolic compounds and their antioxidative properties. Antioxidative properties were evaluated by various different methods: scavenging effect on the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and hydroxyl radical, anti‐lipid peroxidation and reducing power assay. The phenolic compound contents were determined by spectrophotometric methods. Extract of Priao‐yak with the highest tannin content showed the strongest reducing power, while extract of Khanti with the highest proanthocyanidin content revealed high scavenging ability on both DPPH and hydroxyl radicals. Stronger antioxidative activity measured by most assays was noted for the extract of Sithong‐bao with a high content of total phenols, proanthocyanidin and tannins. The results suggest that specific phenolic constituents in the extract could be responsible for the different antioxidant properties observed in different cultivars. Furthermore, seed coat extract of Sithong‐bao may be a potential source of natural antioxidant to be developed into nutraceuticals. PRACTICAL APPLICATIONS Components of Tamarindus indica L., a tree indigenous to India and South‐East Asia, have long been used as a spice, food component and traditional medicine. According To traditional medicine, the tamarind pulp is used as a digestive, carminative, laxative, expectorant and blood tonic; the seeds are used as an anthelmintic, antidiarrheal and emetic. In addition, the seed coat is used to treat burns and aid wound healing as well as as an antidysenteric. Recent studies have demonstrated polyphenolic constituents with more potent antioxidant and anti‐inflammatory activities of T. indica seed coat extract. Therefore, seed coat extracts of T. indica have economic potential for development into health promotion products as well as natural preservatives to increase the shelf life of food by preventing lipid peroxidation.