Separation of Antioxidant-Rich Alternanthera Sessilis Red Extracts by Sephadex LH-20 and Identification of Polyphenols Using HPLC-QToF-MS/MS.

This study aimed to fractionate Alternanthera sessilis Red (ASR) crude extracts and determine their antioxidant activities as well as the related active components in the whole plant. ASR was extracted with water and ethanol, and further separated using a Sephadex LH-20 column. Following the assessments of the polyphenolic contents and antioxidant activities of crude extracts (H2 OASR and EtOHASR ) and fractions, a HPLC-QToF analysis was performed on the crude extracts and selected fractions (H2 OASR FII and EtOHASR FII). Three water fractions (H2 OASR FI, FII and FIII) and four ethanolic fractions (EtOHASR FI, FII, FIII and FIV) were derived from their crude extracts, respectively. EtOHASR FII exhibited the greatest total phenolic content (120.41 mg GAE/g fraction), total flavonoid content (223.07 mg RE/g fraction), and antioxidant activities (DPPH IC50 =159.43 µg/mL; FRAP=1.93 mmol Fe2+ /g fraction; TEAC=0.90 mmol TE/g fraction). Correlation analysis showed significant (p<0.01) positive correlations between both TPC (r=0.748-0.970) and TFC (r=0.686-0.949) with antioxidant activities in the crude extracts and fractions. Flavonoids were the major compounds in the four selected samples tentatively identified using HPLC-QToF-MS/MS, with the highest number of 30 polyphenol compounds detected in the most active fraction, EtOHASR FII.

Alternanthera sessilis: Uncovering the nutritional and medicinal values of an edible weed.

ETHNOPHARMACOLOGICAL RELEVANCE: Weeds are often considered undesirable as they interfere with the habitat of native plants, and therefore they are underestimated and underutilised. In fact, some edible weeds have beneficial nutritional and medicinal values. Alternanthera sessilis (L.) R. Br. ex DC., an edible medicinal weed is a species of the Amaranthaceae family that consists of two cultivars: green and red. Local communities in different regions have traditionally consumed the plants as food and medicine, with the green cultivar being applied to relieve pain, treat wound healing, dysentery, asthma and hypertension, while the red cultivar is applied to prevent cardiovascular and liver diseases in general. AIM OF THE STUDY: The present review intends to provide an in-depth discussion and scientific basis of A. sessilis green and red's health-promoting properties in relation to their ethnobotanical use, nutritional components and bioactive compounds. MATERIALS AND METHODS: The literature search was conducted using relevant keywords on scientific search engines such as the Web of Science, Google Scholar, Medline and Scopus. RESULTS: A. sessilis shows potent antioxidant activity as a result of its diverse phytochemical constituents, such as polyphenols, terpenes, alkaloid and carotenoids in addition to its nutritional components: vitamin C, E and unsaturated fatty acids, which contribute to its various bioactive properties: anti-microbial and anthelmintic, anti-diabetic, lipid lowering, anti-inflammatory and analgesic activities, anti-cancer and other biological activities. Toxicity evaluation revealed the absence of adverse effect of A. sesslis extracts. CONCLUSION: A. sessilis has a great potential to be used as complementary medicine and ingredients for pharmaceuticals, nutraceuticals and functional foods, instead of being regarded as a pest. Prospects for enhancing the development and commercialisation of this edible medicinal weed as a high value health-promoting product are suggested.