An evaluation of the phytochemical composition, antioxidant and cytotoxicity of the leaves of Litsea elliptica Blume – An ethnomedicinal plant from Brunei Darussalam

Abstract

Litsea elliptica is traditionally believed to prevent and treat stomach ulcers, cancer, fever and headaches. This study investigates the phytochemical composition, antioxidant and cytotoxic effects of L. elliptica leaf extracts. The phytochemical content was determined via GCMS analysis and total phenolic content (TPC) and total flavonoid content (TFC) were analysed using the Folin-Ciocalteu and aluminium-chloride assays. Antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging and ferric-ion reducing antioxidant power (FRAP) assays, whereas cytotoxicity was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and calcein/ethidium viability assays. The mechanism of cytotoxicity was investigated using Annexin V/propidium iodide. Modifications in the mitochondria were investigated using MitoTracker Red CMXRos. Ten and twenty-six compounds were characterized in the young-leaf and mixed-leaves extracts, respectively. The young-leaf methanolic extract demonstrated the highest antioxidant capacity of at least four-folds greater than the mixed-leaves and ethanolic extracts. The methanolic extract also had higher TPC and TFC values compared to the ethanolic extract. Although the mixed L. elliptica leaves had lower antioxidant capacities compared to the young leaves, the mixed leaves extract has demonstrated greater cytotoxicity against the A549 cancer cell line. Further investigation revealed that the L. elliptica leaves-induced cytotoxicity on A549 cells was possibly via the non-inflammatory mitochondria-mediated apoptotic pathway. Overall, our results showed the potential of the L. elliptica leaves possessing cytotoxic activities against carcinoma cells where the compounds present can be further investigated for its therapeutic application.

In vitro and in silico studies of the potential cytotoxic, antioxidant, and HMG CoA reductase inhibitory effects of chitin from Indonesia mangrove crab (Scylla serrata) shells

“…This indicated that the toxic effect was due to the presence of antioxidant compounds, which contributed to reducing the number of HepG2 cell. These findings are consistent with previous studies that chitin had moderate antioxidant activity ( Goh et al, 2022 ).…”

“…Antioxidants often interacted with DPPH radicals through the mechanism of proton donation. The presence of concentrated unpaired electrons led to the formation of the chitin radical compound, which has very low energy and was significantly less reactive, thereby increasing the ability to suppress DPPH free radicals ( Goh et al, 2022 ).…”