Supaluk Prachayasittikul

8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents.

Considerable attention has been given on the search for novel anticancer drugs with respect to the disease sequelae on human health and well-being. Triazole is considered to be an attractive scaffold possessing diverse biological activities. Structural modification on the privileged structures is noted as an effective strategy towards successful design and development of novel drugs. The quantitative structure–activity relationships (QSAR) is well-known as a powerful computational tool to facilitate the discovery of potential compounds. In this study, a series of thirty-two 1,2,3-triazole derivatives (1–32) together with their experimentally measured cytotoxic activities against four cancer cell lines i.e., HuCCA-1, HepG2, A549 and MOLT-3 were used for QSAR analysis. Four QSAR models were successfully constructed with acceptable predictive performance affording R CV ranging from 0.5958 to 0.8957 and RMSECV ranging from 0.2070 to 0.4526. An additional set of 64 structurally modified triazole compounds (1A–1R, 2A–2R, 7A–7R and 8A–8R) were constructed in silico and their predicted cytotoxic activities were obtained using the constructed QSAR models. The study suggested crucial moieties and certain properties essential for potent anticancer activity and highlighted a series of promising compounds (21, 28, 32, 1P, 8G, 8N and 8Q) for further development as novel triazole-based anticancer agents.

Background: Strychnos lucida R. Br. (Loganiaceae), a well-known indigenous medicine in Timor Leste, has been used for the treatment of ailments such as malaria, diarrhoea, fever, hypertension, cancer, diabetes mellitus and skin infections. Its pharmacological activity has never been reported. The aim of this study was to determine the biological activities of S. lucida, including antimicrobial, antioxidant and anticancer activities. Materials and methods: The stem, stem bark, twig and leaves of S. lucida were extracted by non-polar (hexane) and polar (ethyl acetate and methanol) solvents. Antimicrobial activity of the plant extracts against 29 microorganisms was evaluated using the agar dilution method and antioxidant properties were determined using DPPH and SOD assays. Anticancer activity was investigated against HepG2, HuCCA-1, A549 and MOLT-3 cell lines using the MTT and XTT assays. Results: It was found that the hexane and ethyl acetate extracts of S. lucida selectively inhibited the growth of Gram positive bacteria (Bacillus subtilis ATCC 6633, Bacillus cereus and Streptococcus pyogenes) with MICs range of 32-128 μg/mL. Antioxidant activities, radical and superoxide scavenging properties, were observed for ethyl acetate and methanol extracts of S. lucida. Particularly, the ethyl acetate extracts selectively showed inhibitory activity against MOLT-3 cells. Notably, the plant extracts showed the relationship between antimicrobial, antioxidant and anticancer activities. Conclusion: The findings support the medicinal usage of S. lucida. Key words: Strychnos lucida; antimicrobial activity; antioxidant activity; anticancer activity

Spilanthes acmella, a well known antitoothache plant with high medicinal usages, has been recognized as an important medicinal plant and has an increasingly high demand worldwide. From its traditional uses in health care and food, extensive phytochemical studies have been reported. This review provides an overview and general description of the plant species, bioactive metabolites and important pharmacological activities including the preparation, purification and in vitro large-scale production. Structure-activity relationships of the bioactive compounds have been discussed. Considering data from the literature, it could be demonstrated that S. acmella possesses diverse bioactive properties and immense utilization in medicine, health care, cosmetics and as health supplements. As a health food, it is enriched with high therapeutic value with high potential for further development.

In the previous studies, the cytotoxicities of anthranilate sulfonamides were investigated. Herein, the bioactivities of 4-substituted (X = NO₂, OCH₃, CH₃, Cl) benzenesulfonamides of anthranilic acid (5-8) are reported. The results revealed that all sulfonamides selectively exerted antifungal activity (25-50 % inhibition) against C. albicans at 4 μg/mL. Furthermore, compounds 6 and 8 show antioxidative (SOD) activity. These sulfonamides, except for 6, selectively display cytotoxic effects toward MOLT-3 cells. It is interesting to note that sulfonamides with electron withdrawing substituent (5, X = NO₂) exhibited the highest cytotoxicity. This study provided preliminary structure-activity relationship of the anthranilic sulfonamides that is useful for further in-depth investigation.