Phenolic Compounds and Antioxidant Activities of Macerated Alpinia Galanga Stems and Leaves

Abstract

Alpinia galanga (A. galanga) is a popular culinary ingredient as well as medicinal herb commonly found in Southeast Asia. Compared to the rhizome of A. galanga, the leaves and stems are always being discarded as waste. In this research, active compounds from the stem and leaves of this plant were extracted using maceration technique with ethanol as solvent at a liquid-solid ratio of 20 ml/g. The influence of maceration time and maceration temperature on total phenolic content (TPC) and antioxidant activities of extract were studied using Folin-Ciocalteu assay and DPPH radical scavenging assay, respectively. The maceration time was from 1 to 5 hr and the maceration temperature was examined from 40 ºC to 70 ºC. Crude extract yield for stems and leaves obtained for all parameters of the maceration process was ˃11%. The highest TPC for leaves was obtained at 1 hr (0.038± 0.02 mg GAE/mg DW) and stems at 4 hr (0.024 ± 0.01 mg GAE/mg DW). Similar trend was also observed for antioxidant activity where the highest antioxidant activity obtained for leaves was at 1 hr (IC50=0.136 ± 0.01 mg/ml) and for stems was at 4 hr (IC50=0.320 ± 0.07 mg/ml). Maceration time however, has no significant influence on TPC (p>0.09) and antioxidant activity (p>0.16) of A. galanga. In terms of temperature, the highest TPC was recorded at 70 ºC for both leaves (0.034 ± 0.003 mg GAE/mg DW) and stems (0.019 ± 0.005 mg GAE/mg DW), while the highest antioxidant activity was from sample extracted at 40 ºC for both leaves (IC50 = 0.076 ± 0.05 mg/ml) and stems (IC50 = 0.454 ± 0.16 mg/ml). The best maceration conditions, considering from the antioxidant activity, for both leaves and stems of A. galanga were concluded at 1 hr and 40 ºC in the viewpoint of both extract quality, energy and cost efficiency.

Effect of Extracted Galangal Rhizome and Gelling Agents on Quality Attributes of Galanga Jelly Product

“…According to the review of total phenolic content and IC 50 of the galangal rhizome extract from water extraction in many research, it was reported that the amount of total phenolic content in galangal rhizome extract derived from water extraction (10% fresh galangal) was 8.25 ± 0.78 mg GAE/g of extraction while the amount of total phenolics in galangal rhizome extract derived from 50% ethanol extraction (10% fresh galangal) was 31.49 ± 4.09 mg GAE/g of extraction and fresh galangal extract derived from water extraction had IC 50 = 54.39 mg/ml, plus fresh galangal extract derived from ethanol extraction had IC 50 = 10.50 mg/ml [18] (pp. 358-365) and [24] (pp. 44-46).…”

“…In addition, 4% galangal extract had a total phenolic of 442.6 ± 69.1 mg GAE/100g, and the IC 50 was 3554.9 ± 55.6 ppb [25] (pp. [24][25]. Nonetheless, the total phenolic content and IC 50 were different due to the extraction methods and the concentration of galangal rhizome.…”

“…Nonetheless, the total phenolic content and IC 50 were different due to the extraction methods and the concentration of galangal rhizome. For example, [18] (p. 362) extracted galangal by distilling galangal powder at 80°C for 3 hours, while [24] (p. 41) used hot water at different temperatures for 1 hour to extract galangal. [25] (p. 23) extracted galangal by boiling galangal before mixing it with distilled water.…”

Recent Findings on Alpinia Galanga (L.) Wild for the Treatment of Arthritis Part-1

“…Most frequently detected compounds are galangin, kaempferol, 1ʹ-acetoxychavicol acetate (ACA), galanganols 1,8-cineole, eucalyptol. Although rhizomes are the most frequently studied, other parts of the plants like leaf 18 , stem 19 , flower 20 , fruit 21 and seeds 22 are also rich in bioactive phytoconstituents.…”