In vitro Bioactivity of Methanol Extracts of Elaeocarpus serratus Leaves and Fruit

Abstract

Plants are getting significant attention globally and the worldwide annual market for herbal products is ~USD 60 billion. Elaeocarpus serratus which is an underutilized fruit crop in Sri Lanka was selected for scientific evaluation. Oven-dried mature leaves and fruit (without the seeds) were subjected to methanol extraction. It was found that the leaf extract showed high phenolic content of 100.62±7.28 mg Gallic acid equivalent (GAE)/g and flavonoid content of 14.72±0.85 mg Quercetin equivalent/g. The fruit also showed phenolic content of 157.35±4.82 mg GAE/g. The extracts showed good antioxidant activity by the DPPH assay: leaf- 38.42 ± 6.18 mg Trolox equivalent (TE)/mg and fruit- 185.95±6.07 mg TE/mg. Similarly, the extracts showed notable anti-oxidant activity by the ORAC assay: leaf- 52.45±7.61 mg TE/mg and fruit- 15.35±3.29 mg TE/mg. The leaf extract also demonstrated high anti-inflammatory activity by the human red blood cell membrane stabilization assay where the highest percentage of inhibition was recorded as 85% and an IC50 of 6×10-5 mg/ml whereas standard ibuprofen showed an IC50 of 5×10-3 mg/ml only. The leaf extract also showed a percentage inhibition of 47% by the protein denaturation egg albumin assay whereas the +ve control ibuprofen showed a similar value (51%). Further, inductively coupled plasma-mass spectrometry data revealed the presence of biologically significant both essential minerals and trace elements such as Na-125.73 ppm, Al-53.06 ppm, Fe-44.43 ppm, Mn-16.71 ppm, Zn-7.93 ppm, and Sr-6.11 ppm in the leaf extract. Furthermore, the leaf demonstrated ~40% of cell growth inhibition, while the fruit showed ~35% growth inhibition in Vero cells after 24 hours of treatment by MTT assay. This study demonstrated noteworthy anti-oxidant and anti-inflammatory activity along with essential minerals, especially in the leaf extract. Further studies are underway to elucidate additional health benefits of the leaf and fruit, by in vitro bioassay since the research on this underutilized plant has been minimal. This work may help to develop processed products such as new preparations of pickles/jams that will instigate economic benefits.