Phytochemical analysis and antioxidant properties of keladi candik (Alocasia longiloba) plant

Alocasia longiloba is one of the medicinal plants in Asia which is underutilized due to lack of knowledge available about it. Alocasia plants having many medicinal uses like
external wound treating property, anti-toxic reputation, anti-bacterial properties and ect. The aim of this study are to determine the total phenolic and flavonoid contents and antioxidant property of A. longiloba plant extracts besides to identify the bioactive compounds in A. longiloba plant extracts showing the activity using GC/MS. In this study, leaf and petiole extracts of the plant prepared in different polarity solvents which are 95% ethanol, 50% ethanol, water and hexane by using Soxhlet extraction method. Total phenolic content and total flavonoid content were determined by using Colorimetric and Folin-reagent methods respectively. Antioxidant potential was determined using DPPH
radical scavenging assay method and ABTS assay method. Finally, GC/MS analysis was done to identify the active compounds present in the plant extracts that shown the activity.

As result, highest total phenolic content of both leaf and petiole parts are shown by hexane extracts with the value of 198.273±0.003 µg/mg GAE and 101.909±0.004
pg/mg GAE respectively. Meanwhile highest total flavonoid content also shown by the hexane leaf extract (78.520±0.003 µg of catechin/mg of extract). Total phenolic content are positively correlated with total flavonoid content with the correlation value of 0.6 and
0.998 for leaf and petiole pan respectively. As for DPPH analysis, highest antioxidant activity with lowest IC₅₀ value was reported in hexane leaf extract (394.88µg/ml) and 50% ethanol petiole extract (985.73µg/ml). However, ABTS analysis showed highest antioxidant activity with the lowest IC₅₀ values for both leaf and petiole parts in 50% ethanol extracts with the value of 1047.32µg/ml and 1960.41µg/ml.

In overall, leaf part showed higher TPC, TFC and antioxidant activity compared to the petiole part. There are positive correlation between total phenolic content and IC₅₀ values of DPPH and ABTS assay for leaf extract while total phenolic content is negatively correlated with IC₅₀ values of DPPH and ABTS assay for petiole extract. GC/MS analysis reported there are six different bioactive compounds that are showing biological activities. Thus, A. longiloba plant are recommended as a plant of pharmaceutical importance based on its antioxidant potential and the bioactive compounds properties present in it.