Antioxidant Activity of Zingiberaceae that Growing in Silokek Geopark Area Rahmat Sarkani Aipama (2210421003) – Biology Department, FMIPA Andalas University Many studies about antioxidant activity of family Zingiberaceae did not pay attention at where they got the materials or where the Zingiberaceae plant growth and come to them. While there is a difference between plant that live in swamp area, highland, lowland, and many different geographical conditions. This study main focus is into knowing the antioxidant activity in Zingiberaceae that lives and grow in Silokek Geopark Area, which is a limestone area in West Sumatera. Antioxidant molecules can be classified in different ways depending on their environment and the functions they perform. Tropical karst tree species exhibit thick leaves with high tissue density, indicative of conservative resources use, which could potentially be sensed remotely using photochemical reflectance index. This also could be possibility that there is difference in physiology, morphology or even composition compound of Zingiberaceae that live in karst area (Geekiyanage et al., 2017). Extreme temperatures, droughts, heavy metals, nutrient shortages, and high salinity are examples of unfavorable environmental factors that can cause oxidative stress in plants. These factors can produce large quantities of reactive oxygen species (ROS). To combat this, cells have a complex antioxidant system with enzymatic and non-enzymatic elements, with phenolic compounds playing a crucial role. Zingiberaceae family is widely distributed in the Southeast Asia region and the plants are characterised based on tuberous or non-tuberous rhizomes and has strong aromatic and medicinal properties. Previous studies have proven that both, A. galanga and K. galanga (Zingiberaceae), extracts have also been found to exhibit pharmacological activities like anti-inflammatory and analgesic, antimicrobial, antioxidant and anticancer (Sani et al., 2019). It is expected that by this study will provide a more complete information about Zingiberaceae antioxidant activity, especially in Zingiberaceae that grow in karst area. This research hopefully will make some preferences in choosing some Zingiberaceae species that going to use as antioxidant compound in some food or anything else. In some previous article that has been released, many talk about the discovery or first report about species in family Zingiberaceae that have conservation value (CV) or even high conservation value (HCV) in limestone area with diversity study and composition. Not going to lie that in plant taxonomy study, it more focused on taxonomy status or diversity and conservation value while we should know about their chemical compound too, especially in vary growth habitat condition. From Appalasamy et al. (2022), their team discovery about 15 new records of wild gingers in Kelantan limestone area and very less of this new record having an information about their antioxidant activity. There is information about essential oils from one of their new record species, Etlingera littoralis, but this species did not use methodologies for antioxidant so we cannot see the antioxidant activity, only the essential oils. The fact that this E. littoralis that use to check it essential oils, and even if we add the method for antioxidant activity like DPPH or ABTS, this species was found in Ayer Itam Dam, Penang, Malaysia by Wong, Sivasothy, Boey, Osman, and Sulaiman (2010), and it is not a limestone area, so the information about antioxidant of Zingiberaceae in limestone area is still none. An article about the diversity of flowering plant in the Geopark Silokek Area, Sijunjung, West Sumatera conducted by Nurainas et al. (2024) resulting a table of flowering plant that grow in limestone area in four sites; Batang Tayeh Waterfall, Sikajai Waterfall, Talago cave, Bukit Subarang. One of the family they collected was Zingiberaceae, with seven species from five genera; Alpinia, Elettariopsis, Globba, Hornstedtia and Zingiber. It also mentioned that two from seven species of family Zingiberaceae that they collected were having important value species, however Nurainas et al. (2024) did not examining the antioxidant activity of this species. In my findings, there is only two species from seven species that Nurainas et al. (2024) collected before have an explanation about their antioxidant activity and one other about its traditional use and antimicrobe potential. This species was, Hornstedtia scyphifera that by John, A, Ojochenemi, and Isaac (2020) use to isolate the phytochemicals and evaluate the potential of the leaves crude extract of its cytotoxicity, antimicrobial and antioxidant. They only using the leaves part of H. scyphifera to aim their work, and collected in Singh, Sarawak, Malaysia. Unfortunately, they did not specify the place where they collected the sample, so we did not know is it a limestone area or not, and that is the missing gap for our study to find the antioxidant activity in Zingiberaceae that grow in Silokek Geopark Area, a limestone area. Another research about H. scyphifera var fusiformis Holtum by Santoni, Efdi, and Suhada (2019) proving the antioxidant activity in this species, yet the sample they use to prove the antioxidant activity not mentioned where they found the sample. Zingiber macradenium that has been found by Nurainas et al. (2024) before also has been examining through ethnobotanical approach by Agustin, Nurainas, Syamsuardi, and Chairul (2021) in Rantih Village, Sawahlunto city and Nagari Sungai Buluh Timur, Padang Pariaman Regency. It resulting that Zingiber macradenium is still used by some people in West Sumatra until now as a mouthwash, itching, backache. The community's traditional knowledge of plants seems to be decreasing, this can be seen from the low UV and ICS values of plants. Zingiber macradenium has potential as an antimicrobial which can be seen from the diameter of its strong inhibitory power (Agustin et al., 2021). The species Hornstedtia conica is examine by Tiwi et al. (2015) to screening the antioxidant activity in several Zingiberaceae, and two of them are that Nurainas et al. were collected. The gap is Tiwi et al. (2015) did not specify where they collected the Zingiberaceae sample, only mentioned that the sample was collected in Sumatera Barat, same cases with (Santoni et al., 2019 and Agustin et al., 2021) so it can be concluded that is still less information about how antioxidant activity in family Zingiberaceae that grow in limestone area. To get the result of antioxidant activity in Zingiberaceae, there is a large variety of in vitro method to quantify antioxidant activity and, it is important to select the proper method to determine which species have the highest antioxidant activity (Chaves et al., 2020). In Sani et al. (2019) was conducting its research about phytochemical, antioxidant and antibacterial of two kinds of Sabah Zingiberaceae by using many methods for every aim they going to achieve. It starts with extraction of the sample by performed a maceration method at room sample and then process by analysing using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. This method is easy and applies to measure the overall antioxidant capacity (Prakash, 2001) and the free radical scavenging activity of fruit and vegetable juices (Sendra et al., 2006). This assay has been successfully utilized for investigating antioxidant properties of wheat grain and bran, vegetables, conjugated linoleic acids, herbs, edible seed oils, and flours in several different solvent systems including ethanol, aqueous acetone, methanol, aqueous alcohol and benzene (Yu, 2001; Parry et al., 2005; Kedare & Singh, 2011). Research about antioxidant activity screening conducted by Tiwi et al. (2015) using Thin Layer Chromatography (TLC) – Bioautography Antioxidant for proving the presence of antioxidant activity, but also using DPPH solution in methanol. It said that the chromatogram profile will look like white yellowish spotting in the thin layer chromatography plate. Same method that Santoni et al. (2019) use to identify antioxidant activity in H. scyphifera var. fusiformis using DPPH as the component to detect the antioxidant by combined it with sample solution and being allowed to react in room temperature for 30 minutes. The result proving that the extract that they use to measure the antioxidant activity having difference in each extract, with methanol extract having the best result, ethyl acetate categorized as moderate, and n-hexane extract as low. Many other studies about antioxidant activity also using the DPPH assay to analysis their extract sample, (Rachkeeree at al., 2018; Handayani et al., 2014) first by making the DPPH solution, and the methanol extract sample and lastly the comparison solution with variative concentration. Other method uses by Batubara, Zahra, Darusman, and Maddu (2016) with ABTS assay {2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)} (Ratnavathi & Komala, 2016), is a cation radical that used to determine antioxidant activity using spectrophotometry. The principle of the antioxidant test used is to measure the ability to ABTS radical activity that will be compared with ascorbic acid. Djide, Mubarak, and Natasya (2022) divided their method using ABTS by making stock solution for ABTS and then measure the uptake ability of the blank solution for comparison with the extract. It is mixture the stock solution with ABTS solution and addition of ethanol for completion and giving solution with vary concentration. Lastly, the solution will measure by spectrophotometer UVVis with its own wave length. The DPPH and ABTS methods measure antioxidant characteristics by analysing the colour change of the antioxidant at different wavelengths. The DPPH method uses the stable DPPH radical, which is reduced by antioxidants, while the ABTS method uses the ABTS radical cation, which is also reduced by antioxidants. The IC50 values are accurate if the antioxidant absorbs the monitored wavelength, but not if it absorbs it (Olszowy & Dawidowicz, 2017). Based on research that has been conducted on the antioxidant activity in family Zingiberaceae, especially focusing on the species that grow in limestone area still there is no idea research yet. Although many studies have optimized the methods to check the antioxidant activity in Zingiberaceae and its taxonomy study about conservation value, specific research on the place where the Zingiberaceae grow did not pay attention, that where they live could make a different in the chemical compound itself. Therefore, this study aims to engage that this knowledge gap needs to be fulfil and research more, so that the continues about this study will increase over a time. Through the use of proven vary methodologies from previous studies and careful evaluation, it is hopes that there is preference in choosing some Zingiberaceae species that going to use as antioxidant compound in some food or anything else, despite its conservation value. For every chance and experiment we try in this research, it will show the brightening way of this research and make a difference in future needs with antioxidant activity in Zingiberaceae, particularly species that grow in limestone area. REFERENCES Agustin, L., Nurainas, N., Syamsuardi, S., & Chairul, C. (2021). Zingiber Macradenium K. Schum, an Endemic Ginger From Sumatera: Traditional use and Antimicrobe Potential. Eduvest, 1(10). https://doi.org/10.36418/edv.v1i10.230 Appalasamy, S., Arumugam, N., Zamri, N. S. A., Fadhlina, A., Kumaran, J. V., & Subramaniam, S. (2022). First Report on Wild Ginger (Family: Zingiberaceae) Species Composition with New Records in Limestone Forests of Kelantan, Peninsular Malaysia. 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