Antibacterial and Antifungal Alkaloids from Asian Angiosperms: Distribution, Mechanisms of Action, Structure-Activity, and Clinical Potentials.

The emergence of multidrug-resistant bacteria and fungi requires the development of antibiotics and antifungal agents. This review identified natural products isolated from Asian angiosperms with antibacterial and/or antifungal activities and analyzed their distribution, molecular weights, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and a library search from 1979 to 2022. One hundred and forty-one antibacterial and/or antifungal alkaloids were identified during this period, mainly from basal angiosperms. The most active alkaloids are mainly planar, amphiphilic, with a molecular mass between 200 and 400 g/mol, and a polar surface area of about 50 Å2, and target DNA and/or topoisomerase as well as the cytoplasmic membrane. 8-Acetylnorchelerythrine, cryptolepine, 8-hydroxydihydrochelerythrine, 6-methoxydihydrosanguinarine, 2'-nortiliacorinine, pendulamine A and B, rhetsisine, sampangine, tiliacorine, tryptanthrin, tylophorinine, vallesamine, and viroallosecurinine yielded MIC ≤ 1 µg/mL and are candidates for the development of lead molecules.

Chemical and pharmacognostical characterization of two Malaysian plants both known as Ajisamat

Ajisamat, an herb commonly used as an aphrodisiac in the Malaysian traditional medicine, corresponds to two different species from different families - Salacia macrophylla Blume, Celastraceae, and Prismatomeris glabra (Korth.) Valeton, Rubiaceae. Macromorphological inspection of the vegetative parts both plants reveals only a slight difference in the arrangement of the petioles. Microscopic investigation of the plants roots used as crude drugs revealed however distinctive anatomical features. Prismatic calcium oxalate crystals and banded paratracheal parenchyma are characteristics of S. macrophylla while P. glabra displays an abundance as crystals. Other features such as vessels diameters and arrangements are also of diagnostic importance. Some of these characters were also identified in the powder of thes e plant materials and proposed for diagnostic purpose. The values for extraction of ethanol and water as well as total ash, acid-insoluble ash, water-soluble ash and sulfated ash were determined for both plants. Phytochemical studies were carried out on hexane and chloroform extracts of S. macrophylla and methanolic extract of P. glabra. S. macrophylla was shown to contain highly oxidized pentacyclic triterpenes while P. glabra contains anthraquinones. The pharmacognostical and hytochemical information can be utilised as the identification tools for Salacia macrophylla and Prismatomeris glabra .

Design, synthesis, in vitro cytotoxicity evaluation and structure-activity relationship of goniothalamin analogs.

A series of six/five member (E/Z)-Goniothalamin analogs were synthesized from commercially available (3,4-dihydro-2H-pyran-2-yl)methanol/5-(hydroxymethyl)dihydrofuran-2(3H)-one in three steps with good to moderate overall yields and their cytotoxicity against lymphoblastic leukemic T cell line (Jurkat E6.1) have been evaluated. Among the synthesized analogs, (Z)-Goniothalamin appeared to be the most active in cytotoxicity (IC50 = 12 µM). Structure-activity relationship study indicates that introducing substituent in phenyl ring or replacing phenyl ring by pyridine/naphthalene, or decreasing the ring size of lactones (from six to five member) do not increase the cytotoxicity.

Phytochemical and cytotoxic investigations of Curcuma mangga rhizomes.

Investigations on the cytotoxic effects of the crude methanol and fractionated extracts (hexane, ethyl acetate) C. mangga against six human cancer cell lines, namely the hormone-dependent breast cell line (MCF-7), nasopharyngeal epidermoid cell line (KB), lung cell line (A549), cervical cell line (Ca Ski), colon cell lines (HCT 116 and HT-29), and one non-cancer human fibroblast cell line (MRC-5) were conducted using an in-vitro neutral red cytotoxicity assay. The crude methanol and fractionated extracts (hexane and ethyl acetate) displayed good cytotoxic effects against MCF-7, KB, A549, Ca Ski and HT-29 cell lines, but exerted no damage on the MRC-5 line. Chemical investigation from the hexane and ethyl acetate fractions resulted in the isolation of seven pure compounds, namely (E)-labda-8(17),12-dien-15,16-dial (1), (E)-15,16-bisnor-labda-8(17),11-dien-13-on (2), zerumin A (3), ß-sitosterol, curcumin, demethoxycurcumin and bis-demethoxycurcumin. Compounds 1 and 3 exhibited high cytotoxic effects against all six selected cancer cell lines, while compounds 2 showed no anti-proliferative activity on the tested cell lines. Compound 1 also demonstrated strong cytotoxicity against the normal cell line MRC-5. This paper reports for the first time the cytotoxic activities of C. mangga extracts on KB, A549, Ca Ski, HT-29 and MRC-5, and the occurrence of compound 2 and 3 in C. mangga.

Antimicrobial and cytotoxic activities of Malaysian endophytes.

Endophytes, which are receiving increasing attention, have been found to be potential sources of bioactive metabolites following the discovery of paclitaxel producing endophytic fungi. In the present study, a total of 348 endophytes were isolated from different parts of 24 Malaysian medicinal plants. Three selected endophytes (HAB10R12, HAB11R3 and HAB21F25) were investigated for their antimicrobial and cytotoxic activities. For antimicrobial activity, HAB10R12 and HAB11R3 were found to be most active against bacteria and fungi, respectively. Their antimicrobial effects were comparable to, if not better than, a number of current commercial antibacterial and antifungal agents. Both HAB10R12 and HAB21F25 were found to be potential anticancer drug candidates, having potent activity against MCF-7 and HCT116 cell lines and warrant further investigation.