Strain BO-07 was isolated from the root tissue of Boesenbergia rotunda (L.) Mansf A. and identified as Streptomyces sp. on the basis of morphology, chemotaxonomy and 16S rDNA sequencing. The fractionation of the crude extract from strain BO-07 cultures led to the isolation of two biphenyls: 3′-hydroxy-5-methoxy-3,4-methylenedioxybiphenyl (1) and 3′-hydroxy-5,5′-dimethoxy-3,4-methylenedioxybiphenyl (2); these compounds and the crude extract had potent antibacterial activity against Gram-positive bacteria, and antioxidant and anticancer activities. These compounds showed the highest activity against Staphylococcus aureus ATCC25932, Bacillus cereus ATCC7064 and Bacillus subtilis ATCC6633 with a minimum inhibitory concentration value of 0.5 µg/ml and minimum bactericidal concentration of 2–8 µg/ml. Compounds 1 and 2 showed the highest (1, 1diphenyl-2-picryl hydrazyl) DPPH antioxidant activity with a scavenging concentration (SC₅₀) value of 85.84 and 88.26 µg/ml, respectively, and also showed strong cytotoxicity against all the three cancer cell lines (HeLa, HepG2 and Huh7) at an IC₅₀ value of 3.04–20.30 μg/ml. Both the compounds were less toxic on normal cells (L929) than on the investigated cancer cell lines.

A series of novel coumarin-3-carboxamide derivatives were designed and synthesized to evaluate their biological activities. The compounds showed little to no activity against gram-positive and gram-negative bacteria but specifically showed potential to inhibit the growth of cancer cells. In particular, among the tested compounds, 4-fluoro and 2,5-difluoro benzamide derivatives (14b and 14e, respectively) were found to be the most potent derivatives against HepG2 cancer cell lines (IC₅₀ = 2.62–4.85 μM) and HeLa cancer cell lines (IC₅₀ = 0.39–0.75 μM). The activities of these two compounds were comparable to that of the positive control doxorubicin; especially, 4-flurobenzamide derivative (14b) exhibited low cytotoxic activity against LLC-MK2 normal cell lines, with IC₅₀ more than 100 μM. The molecular docking study of the synthesized compounds revealed the binding to the active site of the CK2 enzyme, indicating that the presence of the benzamide functionality is an important feature for anticancer activity.

2,5-Diketopiperazine derivatives, consisting of benzylidene and alkylidene substituents at 3 and 6 positions, have been considered as a core structure for their antiviral activities. Herein, the novel N-substituted 2,5-Diketopiperazine derivatives were successfully prepared and their antiviral activities against influenza virus were evaluated by monitoring viral propagation in embryonated chicken eggs. It was found that (3Z,6Z)-3-benzylidene-6-(2-methyl propylidene)-4-substituted-2,5-Diketopiperazines (13b–d), (3Z,6E)-3-benzylidene-6-(2-methylpropyli dene)-1-(1-ethyl pyrrolidine)-2,5-Diketopiperazine (14c), and Lansai-C exhibited negative results in influenza virus propagation at a concentration of 25 µg/mL. Additionally, molecular docking study revealed that 13b–d and 14c bound in 430-cavity of neuraminidase from H5N2 avian influenza virus and the synthesized derivatives also strongly interacted with the key amino acid residues, including Arg371, Pro326, Ile427, and Thr439.

A series of tetrahydro-ß-carbolines substituted with an alkyl or acyl side chain was synthesized and screened for its antifungal activity against plant pathogenic fungi (Bipolaris oryzae, Curvularia lunata, Fusarium semitectum, and Fusarium fujikuroi). The structure activity relationship revealed that the substituent at the piperidine nitrogen plays an important role for increasing antifungal activities. In this series, 2-octyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3g) displayed potent antifungal activities with a minimum inhibitory concentration of 0.1 μg/mL, including good inhibitory activity to the radial growth of fungus at a concentration of 100 μg/mL compared to amphotericin B.

Background and Objective: The AL22 strain was isolated from the rhizosphere soil of Alpinia galanga (L.) Willd (Zingiberaceae) and identified as Microbispora sp., by analysing its morphology, chemotaxonomy and 16S rDNA sequence. Previous studies demonstrated the bactericidal effects of its crude extract against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. The present study aimed to isolate the major compounds and evaluate their biological properties. Materials and Methods: Silica gel column chromatography and thin-layer chromatography were used for the purification and identification of 3,4-dihydro-lactucin (compound 1) and umbelliferone (compound 2) by NMR and mass spectrometry, respectively. Antibacterial and anticancer activities were carried out. Results: The bioassay studies illustrated that compound 1 had antibacterial activity against gram-positive bacteria, with its minimum inhibitory concentration and minimum bactericidal concentration of 16-32 and 64-128 μg mL1, respectively. The crude extract and purified compounds showed weak cytotoxic activity on the L929 and Vero cells with IC50 values >512.00 μg mL1. The cytotoxicity of compound 1 was observed in the MDA-MB-231 and HeLa cells with IC50 values of 37.62 and 75.34 μg mL1, respectively, while its IC50 value against the HepG2 cells was 456.67 μg mL1. Conclusion: These findings showed that compound 1 of Microbispora sp., AL22 exhibited antibacterial and anticancer activities. Extensive studies on 3,4-dihydro-lactucin could lead to the development of beneficial approaches for managing bacterial infections and cancer.

Sweet Basil (Ocimum basilicum Linn.) has a variety of therapeutic properties, including antimicrobial activity. This study aimed to determine the antibacterial activity of the major chemical components in the crude extract against methicillin resistant Staphylococcus aureus (MRSA) isolated from the clinical specimens. TLC and column chromatography resulted in the separation of two major compounds. On the basis of the spectral data, they were identified as linalool (1) and 1,8-cineole (2). Antibacterial activity of crude extract and isolated compounds was evalusted by disc diffusion, MIC and MBC against 9 multi-drug resistance S. aureus isolated from clinical specimens. The crude extract and isolated compounds exhibited an excellent antimicrobial activity at a dose level of 34.5 mg/disc for disc diffusion method. The crude extract and linalool showed higher activity against tested MRSA with MIC (<0.09 mg/ml) and MBC (≤ 0.09 to 0.38 mg/ml) than 1,8-cineole. The results suggest once again that the antimicrobial activity of the crude extract and major isolated compounds, linalool and 1,8-cineole are a resultant of the antibacterial property against MRSA.