Cytotoxic constituents from the stems of Clausena lansium (Lour.) Skeels

Ligand-Dependant Selective Synthesis of Mono- and Dialkenylcarbazoles through Rhodium(III)-Catalyzed C-H Alkenylation

The C-H alkenylation of N-acetylcarbazoles proceeds smoothly at the C1-position in the presence of a cationic Cp*Rh(III) catalyst to produce 1-alkenylcarbazoles. The use of a cationic Cp^E Rh(III) catalyst enables further alkenylation to give 1,8-dialkenylcarbazoles. The direct alkenylation procedure in combination with the ready removal of the acetyl directing group provides a straightforward synthetic pathway to 1- and/or 8-alkenyl-N-H-carbazole derivatives. One of 1-alkenyl-N-H-carbazoles obtained by the present C-H alkenylation/deacetylation exhibits solvatochromism.

Phytocompounds as an Alternative Antimicrobial Approach in Aquaculture

Despite culturing the fastest-growing animal in animal husbandry, fish farmers are often adversely economically affected by pathogenic disease outbreaks across the world. Although there are available solutions such as the application of antibiotics to mitigate this phenomenon, the excessive and injudicious use of antibiotics has brought with it major concerns to the community at large, mainly due to the rapid development of resistant bacteria. At present, the use of natural compounds such as phytocompounds that can be an alternative to antibiotics is being explored to address the issue of antimicrobial resistance (AMR). These phytocompounds are bioactive agents that can be found in many species of plants and hold much potential. In this review, we will discuss phytocompounds extracted from plants that have been evidenced to contain antimicrobial, antifungal, antiviral and antiparasitic activities. Further, it has also been found that compounds such as terpenes, phenolics, saponins and alkaloids can be beneficial to the aquaculture industry when applied. This review will focus mainly on compounds that have been identified between 2000 and 2021. It is hoped this review will shed light on promising phytocompounds that can potentially and effectively mitigate AMR.

The anticancer activity of carbazole alkaloids

Chemotherapy is the first choice for the majority of cancers, but severe side effects and drug resistance restrict the actual clinical efficacy. Carbazole alkaloids, mainly from the Rutaceae family, possess favorable donor ability, good planarity, rich photophysical properties, and excellent biocompatibility. Carbazole alkaloids could not only intercalate in DNA but could also inhibit telomerase and topoisomerase and regulate protein phosphorylation. Hence, carbazole alkaloids are useful in providing lead hits/candidates for the development of novel anticancer agents. This review summarizes the research progress made regarding the anticancer properties of carbazole alkaloids, covering articles published from January 2010 to June 2021.

Anti-MRSA Constituents from Ruta chalepensis (Rutaceae) Grown in Iraq, and In Silico Studies on Two of Most Active Compounds, Chalepensin and 6-Hydroxy-rutin 3',7-Dimethyl ether

Ruta chalepensis L. (Rutaceae), a perennial herb with wild and cultivated habitats, is well known for its traditional uses as an anti-inflammatory, analgesic, antipyretic agent, and in the treatment of rheumatism, nerve diseases, neuralgia, dropsy, convulsions and mental disorders. The antimicrobial activities of the crude extracts from the fruits, leaves, stem and roots of R. chalepensis were initially evaluated against two Gram-positive and two Gram-negative bacterial strains and a strain of the fungus Candida albicans. Phytochemical investigation afforded 19 compounds, including alkaloids, coumarins, flavonoid glycosides, a cinnamic acid derivative and a long-chain alkane. These compounds were tested against a panel of methicillin-resistant Staphylococcus aureus (MRSA) strains, i.e., ATCC 25923, SA-1199B, XU212, MRSA-274819 and EMRSA-15. The MIC values of the active compounds, chalepin (9), chalepensin (10), rutamarin (11), rutin 3′-methyl ether (14), rutin 7,4′-dimethyl ether (15), 6-hydroxy-rutin 3′,7-dimethyl ether (16) and arborinine (18) were in the range of 32–128 µg/mL against the tested MRSA strains. Compounds 10 and 16 were the most active compounds from R. chalepensis, and were active against four out of six tested MRSA strains, and in silico studies were performed on these compounds. The anti-MRSA activity of compound 16 was comparable to that of the positive control norfloxacin (MICs 32 vs 16 μg/mL, respectively) against the MRSA strain XU212, which is a Kuwaiti hospital isolate that possesses the TetK tetracycline efflux pump. This is the first report on the anti-MRSA property of compounds isolated from R. chalepensis and relevant in silico studies on the most active compounds.

Anti-inflammatory and cytotoxic carbazole alkaloids from Murraya kwangsiensis

Chemical investigation of the traditional Chinese medicine, Murraya kwangsiensis, led to the isolation of 16 undescribed biscarbazole alkaloids, kwangsines A-M, two undescribed natural products, (+/-)-bispyrayafoline C, and 19 known monomeric analogues. (±)-Bispyrayafoline C and (±)-kwangsines A-C are four pairs of biscarbazole atropisomers, and they were separated by chiral HPLC to obtain the optically pure compounds. The structures of the undescribed compounds were elucidated on the basis of HRESIMS and NMR data analysis. Their absolute configurations were assigned via comparison of the specific rotation, ECD exciton coupling method, as well as comparison of experimental and calculated ECD data. A compound showed significant inhibition on NO production in lipopolysaccharide-stimulated BV-2 microglial cells, and four compounds exhibited moderate cytotoxicities against HepG2 cells, with IC₅₀ values less than 20 μM.

Evaluation of anti-proliferative activity of medicinal plants used in Asian Traditional Medicine to treat cancer

ETHNOPHARMACOLOGICAL RELEVANCE

The extensive biodiversity of plants in Southeast Asia and inadequate research hitherto warrant a continued investigation into medicinal plants. On the basis of a careful review of fresh medicinal plant usage to treat cancer from previous ethnobotanical interviews in Singapore and from the traditional uses of the indigenous plants, fresh leaves of seven locally grown medicinal plant species were evaluated for anti-proliferative activity.

AIM OF THE STUDY

To evaluate the anti-proliferative activity of local medicinal plant species Clausena lansium Skeels, Clinacanthus nutans (Burm. f.) Lindau, Leea indica (Burm. f.) Merr., Pereskia bleo (Kunth) DC., Strobilanthes crispus (L.) Blume, Vernonia amygdalina Delile and Vitex trifolia L.

MATERIALS AND METHOD

Fresh, healthy and mature leaves of the seven medicinal plants were harvested from various locations in Singapore and Malaysia for Soxhlet, ultrasonication and maceration extractions in three different solvents (water, ethanol and methanol). Cell proliferation assay using water soluble tetrazolium salt (WST-1) assay was performed on twelve human cancer cell lines derived from breast (MDA-MB-231, T47D), cervical (C33A), colon (HCT116), leukemia (U937), liver (HepG2, SNU-182, SNU-449), ovarian (OVCAR-5, PA-1, SK-OV-3) and uterine (MES-SA/DX5) cancer.

RESULTS

A total of 37 fresh leaf extracts from seven medicinal plants were evaluated for their anti-tumour activities in twelve human cancer cell lines. Of these, the extracts of C. lansium, L. indica, P. bleo, S. crispus, V. amygdalina and V. trifolia exhibited promising anti-proliferative activity against multiple cancer cell lines. Further investigation of selected promising leaf extracts indicated that maceration methanolic extract of L. indica was most effective overall against majority of the cancer cell lines, with best IC₅₀ values of 31.5 ± 11.4 µg/mL, 37.5 ± 0.7 µg/mL and 43.0 ± 6.2 µg/mL in cervical C33A, liver SNU-449, and ovarian PA-1 cancer cell lines, respectively.

CONCLUSION

The results of this study provide new scientific evidence for the traditional use of local medicinal plant species C. lansium, L . indica, P. bleo, S. crispus, V. amygdalina and V. trifolia in cancer treatment. These results highlight the importance of the upkeep of these indigenous plants in modern society and their relevance as resources for drug discovery.

Anticancer carbazole alkaloids and coumarins from Clausena plants: A review

Pharmaceutical research has focused on the discovery and development of anticancer drugs. Clinical application of chemotherapy drugs is limited due to their severe side effects. In this regard, new naturally occurring anticancer drugs have gained increasing attention because of their potential effectiveness and safety. Fruits and vegetables are promising sources of anticancer remedy. Clausena (family Rutaceae) is a genus of flowering plants and includes several kinds of edible fruits and vegetables. Phytochemical and pharmacological studies show that carbazole alkaloids and coumarins from Clausena plants exhibit anticancer activity. This review summarizes research progresses made in the anticancer properties of plants belonging to Clausena; in particular, compounds with direct cytotoxicity, cell cycle arrest, apoptosis induction, and immune potentiation effects are discussed. This review reveals the potential use of plants from Clausena in preventing and treating cancer and provides a basis for development of relevant therapeutic agents.

Carbazole alkaloids isolated from the branch and leaf extracts of Clausena lansium

The present study carried out a phytochemical investigation of the methanol extract of the branches and leaves of Clausena lansium and afforded nine carbazole alkaloids (compounds 1-9) including two new carbazole alkaloids, claulansiums A and B (compounds 1 and 2). The new compounds were elucidated on the basis of extensive spectroscopic data (MS, NMR, IR, and UV) and the known compounds were identified by comparing spectroscopic data with those reported in literature. All the isolated compounds were tested for their cytotoxic activity against A549 and Hela cancer cell lines. Our results showed that compounds 2-6 exhibited varying degrees of cytotoxicity to cancer cells, with IC₅₀ values ranging from 8.67 to 98.89 μmol·L^-1.

Clausoxamine, an alkaloid possessing a 1,3-oxazine-4-one ring from the seeds of Clausena lansium and the anti-obesity effect of lansiumamide B

One alkaloid with an unprecedented skeleton and one alkaloid with anti-obesity effect were isolated from the seeds of Clausena lansium.