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

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.

Systematic Review of Medicinal Plants Used for Treatment of Diabetes in Human Clinical Trials: An ASEAN Perspective.

Traditionally, there are some medicinal plants believed to treat diabetes, as they have been proven in research studies to possess antidiabetic properties, such as improved insulin sensitivity and hypoglycemic activities, due to their high level of phenolic compounds, flavonoids, terpenoids, alkaloids, and glycosides. We conducted a systematic review to identify potential medicinal plants used during human clinical trials in the Association of Southeast Asian Nation (ASEAN) countries on prediabetic or type 2 diabetic individuals and to potentially identify any bioactive compounds involved in effectively treating symptoms of diabetes such as lowering of blood glucose. A total of 1209 reference titles were retrieved from four selected databases (Science Direct, Scopus, Springer Link, and PubMed) and only three met the inclusion criteria. Upon evaluation of the selected articles, four medicinal plants were identified: turmeric (Curcuma longa), garlic (Allium sativum L.), bitter melon (Momordica charantia), and Rosella flower (Hibiscus sabdariffa L.). Of these, only the bitter melon study did not show any significant change in the blood glucose of participants after intervention. This review demonstrates the limitations in published articles of human clinical trials for medicinal plants' intervention for diabetes. Upon further investigations on the four identified medicinal plants included in the animal studies, the findings showed positive effects in the management of diabetes, such as hyperglycemia. Hence, further testing and standardization of the methods in the studies can be suggested for human clinical trials for reliable data collections such as methods of extract preparation, duration of intervention, and conditions set for the study design.

Physicochemical analyses, antioxidant, antibacterial, and toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam.

In this study, the physicochemical, antioxidant, antibacterial properties, and the toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam were investigated. Propolis particles of different sizes were extracted from raw propolis using various volume fractions of ethanol in water. Spectroscopic analyses were utilized to characterize the chemical structures, functional groups, as well as absorbance and fluorescence properties. The total antioxidant capacity of propolis particles, which was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to increase with volume fraction of ethanol. The maximum antioxidant capacity was as high as 317.65 mg ascorbic acid equivalent per gram of propolis particles. All of the propolis particles showed antibacterial activity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The diameters of the inhibition zone were either significantly higher or equivalent to those of two standard antibiotics (rifampicin and streptomycin), suggesting strong antibacterial activity. The toxicity studies of propolis particles against Caenorhabditis elegans revealed that they are non-toxic after 24 h exposure. Overall findings suggest that H. itama propolis particles are not only an important source of natural antioxidants that could be beneficial for human health, but they have potentials as antimicrobial against bacteria.

Voltammetric and spectroscopic determination of polyphenols and antioxidants in ginger (Zingiber officinale Roscoe).

Ginger (Zingiber officinale) is widely consumed as an important spice or a common condiment in food and beverages. This study focuses on the determination of pungent and bioactive components in ginger and their antioxidant activity using voltammetric and spectroscopic methods. Gas chromatography-mass spectroscopy analysis revealed that the major components of the pungent compounds were zingerone, shogaols, gingerols, paradols, wikstromol, and carinol. Using spectroscopic methods, the antioxidant capacity of ginger aqueous extract was found to be 16.0 µmol gallic acid equivalent (GAE) per gram of ginger extract, and the total phenolic and flavonoid content was estimated to be 7.8 mg GAE/g ginger extract and 15.4 mg Quercetin equivalent (QE) per gram of ginger extract, respectively. Electroanalytical quantification estimated the antioxidant capacity of the ginger infusion to be 23.5 µmol GAE/g ginger extract, which is slightly higher than that estimated using chemical assay. The results may provide useful information for the development of ginger processing and utilization as a flavoring agent, and for our understanding of ginger as a source of natural antioxidants.

Physicochemical properties, antioxidant capacities, and metal contents of virgin coconut oil produced by wet and dry processes.

Different from cooking oils which contain long-chain fatty acids, virgin coconut oil (VCO) has high medium-chain fatty acids, making it a potential functional food which can provide some health benefits. In this study, our objective is to investigate the physicochemical properties, antioxidant capacity, and metal contents of the VCO extracted through four different processing methods: chilling and centrifugation; fermentation; direct micro expelling-oven dried; and direct micro expelling-sun-dried processes. We found that the physicochemical properties, including moisture content, refractive index, viscosity, iodine value, saponification value, peroxide value, free fatty acid, and fatty acid content, of all the VCO conform to the Asian and Pacific Coconut Community (APCC) standard. All of the VCO predominantly contains lauric acid which is in the range of 48.40%-52.84% of the fatty acid content. The total phenolic content and DPPH radical-scavenging activity (IC 50) of the VCO was obtained to be in the range of 1.16-12.54 mg gallic acid equivalents (GAE)/g and 7.49-104.52 mg/ml, respectively, and the metal contents in the VCO were within the acceptable range of the recommended APCC limit. These findings ensure good quality and safety assurance of the VCO produced from the coconut grown in Brunei Darussalam through the different processing methods.

Ethnobotanical review and pharmacological properties of selected medicinal plants in Brunei Darussalam:Litsea elliptica, Dillenia suffruticosa, Dillenia excelsa, Aidia racemosa, Vitex pinnata and Senna alata

The aim of the current study is to review the medicinal properties of the plants found in Brunei Darussalam namely Litsea elliptica, Dillenia suffruticosa, Dillenia excelsa, Aidia racemosa, Vitex pinnata and Senna alata. The known phytochemical constituents of these plants and their ability to bring about a range of biological activities are included in this review. These plants have been used traditionally for a multitude of diseases and illnesses. There is a lot of untapped potential in these medicinal plants which could cure multiple diseases.