Arecanut (Areca catechu L.) seed is an important by-product of commercial crop Arecanut planted in tropical or sub-tropical regions. This study for the first time investigated the phyto-chemical compositions and bio-activities of the Arecanut seed extracts extracted by conventional solvents and deep eutectic solvents (DESs). Results showed that the Arecanut seed extracts obtained by the screened DESs exhibited the highest total alkaloid content (TAC, 33.92 mg ARE/g DW), moderate total phenolic content (TPC) and total flavonoid content (TFC). However, high TPC (57.92 mg GAE/g DW) and TFC (427.56 mg RE/g DW) were obtained by acetone and 50 % EtOH, respectively. Ethyl acetate extracts yielded the lowest TPC (0.74 mg GAE/g DW), TFC (4.24 mg RE/g DW) and TAC (0.62 ARE/g DW). A total of 32 compounds (phenolics, flavonoids, and alkaloids) were identified in the Arecanut seed extracts by using high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF/MS) method. Among them, gallic acid, (-)-gallocatechin, (-)-epigallocatechin, D-catechin, isorhamnetin-3-O-galactoside, arecaine, arecoline, and guvacoline were the main compounds. Additionally, two kinds of DESs (L-Proline-Ethylene glycol and L-Proline-Lactic acid) extracts exhibited superior properties on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS⁺), hydroxyl (OH⁻) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activities, ferric reducing antioxidant power (FRAP), reducing power, cupric reducing antioxidant capacity (CUPRAC), inhibitory ability of α-glucosidase and anti-bacterial activity as compared with the extracts extracted by other solvents. Multivariate analysis results revealed that the extraction solvents significantly affected the phytochemical constituents and biological activities of the Arecanut seed extracts. In conclusion, Arecanut seed is a potential source enriched in natural antioxidants for application in the medicinal aspects. Additionally, the present work provided eco-friendly DESs for high-efficient extracting the useful active compounds from Arecanut seed.

槟榔（槟榔L.) 种子是热带或亚热带地区种植的经济作物槟榔的重要副产品。本研究首次研究了用常规溶剂和低共熔溶剂 (DESs) 提取的槟榔种子提取物的植物化学成分和生物活性。结果表明，经筛选的 DES 获得的槟榔种子提取物表现出最高的总生物碱含量（TAC，33.92 mg ARE/g DW）、中等的总酚含量（TPC）和总黄酮含量（TFC）。然而，高 TPC (57.92 mg GAE/g DW) 和 TFC (427.56 mg RE/g DW) 分别通过丙酮和 50% EtOH 获得。乙酸乙酯提取物产生最低的 TPC (0.74 mg GAE/g DW)、TFC (4.24 mg RE/g DW) 和 TAC (0.62 ARE/g DW)。共 32 种化合物（酚类、黄酮类、通过使用高效液相色谱结合电喷雾电离四极杆飞行时间质谱 (HPLC-ESI-QTOF/MS) 方法鉴定了槟榔种子提取物中的生物碱和生物碱。其中，没食子酸、(-)-没食子儿茶素、(-)-表没食子儿茶素、D-儿茶素、异鼠李素-3-O-半乳糖苷、槟榔碱、槟榔碱和番石榴碱是主要化合物。此外，两种DESs（L-脯氨酸-乙二醇和L-脯氨酸-乳酸）提取物对2,2'-叠氮基-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS ⁺）、羟基（ OH ^- )和 2,2-diphenyl-1-picrylhydrazyl (DPPH ) 自由基清除活性、铁还原抗氧化能力 (FRAP)、还原能力、铜还原抗氧化能力 (CUPRAC)、α抑制能力-葡萄糖苷酶和抗菌活性与其他溶剂提取的提取物相比。多元分析结果表明，提取溶剂显着影响槟榔种子提取物的植物化学成分和生物活性。总之，槟榔种子是一种富含天然抗氧化剂的潜在来源，可用于药用。此外，目前的工作为从槟榔种子中高效提取有用的活性化合物提供了环保的 DES。