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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.

Background: Dillenia suffruticosa (Griff.) Mart. has been traditionally used to promote wound healing, relieve rheumatism, fever and some cancerous growths. The leaves of the local variety of D. suffruticosa lack scientific studies on its biological applications in the context of antibacterial, antioxidant and cytotoxic activities. Objective: To evaluate the antioxidant, antibacterial and cytotoxic properties of the leaves of D. suffruticosa from Brunei Darussalam. Methods: The leaves were extracted using 80% (v/v) methanol, 80% (v/v) ethanol and aqueous. The antioxidant capacities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2’-azino-bis(3-ethylbenzothia zoline-6-sulfonic acid) (ABTS) radical scavenging and ferric ion reducing antioxidant power (FRAP) assays. The FolinCiocalteu and aluminium chloride colorimetric assays were also used to evaluate the total phenolic and flavonoid contents. The antibacterial and cytotoxic activities of the extracts were determined using the Kirby-Bauer disc diffusion and MTT (3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell proliferation assays. Results: The methanolic extract of the D. suffruticosa leaves displayed the highest antioxidant activity despite having comparable phenol content when extracted using the ethanol extraction solvent. The methanolic extract also demonstrated antibacterial activity on Staphylococcus aureus at a concentration of 50 mg/mL or above. The cytotoxicity of the methanolic extract was higher against the CaSki cell line than the A549 lung cancer cell line in the first 24 h but became more cytotoxic against A549 than CaSki at 48 h and 72 h. Conclusion: Our findings suggest that the methanolic extract of the leaves of D. suffruticosa from Brunei Darussalam has significant antioxidant and antibacterial activity against S. aureus and moderate cytotoxicity against A549 and CaSki cell lines.

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