The polyphenolic profiles and antioxidant activities of the water extracts of Barringtonia racemosa shoots (leaves and stems) were explored. Two methods, freeze drying and air drying, for preparation of the shoots, were also compared. Freeze drying was better as air drying caused 5-41% reduction of polyphenols. Three phenolic acids and three flavonoids were identified, using UHPLC. The descending order of polyphenols in the leaves and stems was gallic acid>ellagic acid>quercetin>protocatechuic acid>rutin>kaempferol. In vitro antioxidant analyses were performed using biological samples. In the LDL oxidation assay, B. racemosa leaf extract (IC50=73.0μg/ml) was better than stem extract (IC50=226μg/ml) at inhibiting the formation of TBARS and lipid hydroperoxides. Similar trends were observed for serum and haemoglobin oxidation. B. racemosa leaf extract was better than its stem extract in delaying the time required to oxidise haemoglobin to methaemoglobin. The high polyphenolic content of B. racemosa shoots could have contributed towards their antioxidative effects.
The fruits of Barringtonia racemosa and Hibiscus sabdariffa have been used in the treatment of abscess, ulcer, cough, asthma, and diarrhea as traditional remedy.
Barringtonia racemosa is a medicinal plant belonging to the Lecythidaceae family. The water extract of B. racemosa leaf (BLE) has been shown to be rich in polyphenols. Despite the diverse medicinal properties of B. racemosa, information on its major biological effects and the underlying molecular mechanisms are still lacking.
The present study compared pH, total soluble solids, vitamin C, and total phenolic contents, antioxidant activities, and α-glucosidase inhibitory activities of 40 fresh juices. The juice of Baccaurea polyneura showed the highest yield (74.17 ± 1.44%) and total soluble solids (32.83 ± 0.27 °Brix). The highest and lowest pH values were respectively measured from the juices of Dimocarpus longan (6.87 ± 0.01) and Averrhoa bilimbi (1.67 ± 0.67). The juice of Psidium guajava gave the highest total phenolic (857.24 ± 12.65 μg GAE/g sample) and vitamin C contents (590.31 ± 7.44 μg AAE/g sample). The juice of Phyllanthus acidus with moderate contents of total phenolics and vitamin C was found to exhibit the greatest scavenging (613.71 ± 2.59 μg VCEAC/g sample), reducing (2784.89 ± 3.93 μg TEAC/g sample), and α-glucosidase inhibitory activities (95.37 ± 0.15%). The juice of Barringtonia racemosa was ranked second in the activities and total phenolic content. Gallic and ellagic acids, which were quantified as the major phenolics of the respective juices, are suggested to be the main contributors to the antioxidant activities. The α-glucosidase inhibitory activity of the juices could be derived from myricetin and quercetin (that were previously reported as potent α-glucosidase inhibitors) in the hydrolyzed juice extracts. The juice of Syzygium samarangense, which was found to be highest in metal chelating activity (82.28 ± 0.10%), also was found to have these phenolics.
Riparian areas hold vast number of flora and fauna with exceptional contributions to the ecosystem. A study was conducted in Sungai Sepetang, Sungai Rembau and Sungai Chukai to identify the insect community in a riparian zone of Peninsular Malaysia. Sampling was conducted in six consecutive months from December 2017 to May 2018 during both day and night using sweep nets. Twenty sampling stations (S1-S20) had been assembled along the riverbanks with an average distance of 200 m between each station. The 17,530 collected insects were from 11 orders and consisted of Diptera, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Orthoptera, Blattodea, Thysanoptera, Mantodea and Odonata. The three most abundant orders were Diptera (33.84%; 5933 individuals), Coleoptera (28.82%; 5053 individuals) and Hemiptera (25.62%: 4491 individuals). The collected insect community consisted of different guilds such as the scavenger, predator, herbivore, pollinator and parasitoid. Sungai Sepetang and Sungai Rembau were dominated by mangrove flora, Sonneratia caseolaris (Myrtales: Lythraceae), while Sungai Chukai was dominated by Barringtonia racemosa. There was a significant difference (p < 0.05) in the composition of insects between the three rivers though clustering analysis showed that the insect communities in Sungai Sepetang and Sungai Rembau were 100% similar compared to Sungai Chukai which consisted of a totally different community. There is a significant negative correlation between abundance of insects with salinity and wind speed at Sungai Chukai and Sungai Sepetang.
Barringtonia racemosa leaf water extract (BLE) had been shown to have high gallic acid (GA) content and BLE has been postulated to have anti-proliferative effects towards colorectal cancer. This study aims to further investigate the mechanism underlying the anti-proliferative effect of BLE in Caco-2 cells and to determine if GA is responsible for the observed effects. Both BLE and GA inhibited Caco-2 cells in a dose-dependent manner. Cells exposed to IC50 concentration of BLE and GA showed reduced antioxidant activities. GA-treated Caco-2 cells experienced higher oxidative stress compared to cells treated with BLE. Both BLE and GA significantly up-regulated the expression of SLC2A1. BLE but not GA, significantly down-regulated the expression of ADH4. Meanwhile, GA but not BLE, significantly up-regulated AKRIB10 and GLO1 but significantly down-regulated HAGH. Alterations in gene expression were coupled with changes in extracellular glucose and pyruvate levels. While BLE decreased intracellular pyruvate, GA did the opposite. Both intracellular and extracellular D-lactate were not affected by either BLE or GA. GA showed more pronounced effects on apoptosis while BLE irreversibly reduced cell percentage in the G0/G1 phase. In conclusion, this study demonstrates the multiple-actions of BLE against Caco-2 cells, potentially involving various polyphenolic compounds, including GA.