Salak (Salacca zalacca) is an underutilised fruit. The bioactivities of this fruit have rarely been studied scientifically. Thus, the present study aimed to determine the antioxidant activity of extracts derived from the peel, fruit and kernel of the Salak fruit, as well as the hypoglycemic and anti-hypertensive properties of Salak peel extracts.,The peel, fruit and kernel of the Salak were extracted using distilled water, methanol and ethanol. Antioxidant activities, angiotensin-converting enzyme (ACE) and alpha-amylase inhibition properties of the extracts were estimated via in vitro standard methods. Besides, the total phenolic content (TPC) and total flavonoid content (TFC) of the extracts were also determined in the present study. The antioxidant activities of different parts of Salak extracts were determined by ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) methods. Percent of radical scavenging properties were calculated via DPPH assay. The hypoglycemic and anti-hypertensive properties of Salak peel were evaluated using alpha-amylase inhibition and ACE assays, respectively.,Fruit extracts of Salak in methanol were found to exhibit the highest TPC (10.27 ± 0.12 mg GAE/g), TFC (11.04 ± 0.89 mg CE/g) and antioxidant properties amongst all samples whereby the TPC and TFC were strongly correlated with antioxidant activities. On the other hand, distilled water extracted Salak kernel showed to have the lowest TPC (0.53 ± 0.05 mg GAE/g), TFC (0.37 ± 0.01 mg CE/g) and antioxidant properties amongst all the Salak extracts. Peel extracts exhibit comparable antioxidant activities with fruit extracts in the current findings. In addition, peel extracts indicated some extend of ACE and alpha-amylase inhibition activities regardless of the solvents used. Methanol and ethanol peel extracts indicated no significant difference (p < 0.05) ACE (98%) and alpha-amylase (90%) inhibition activities. However, distilled water extracted Salak peel showed significantly lower ACE and alpha-amylase inhibition in comparison to methanol and ethanol peel extracts.,The present findings suggested that the fruit of Salak exhibits the highest antioxidant properties, followed by the peel and lastly, the kernel, which shows the lowest antioxidant properties amongst all the samples. The results also indicated that the peel extracts have ACE and alpha-amylase inhibition activities.

中文翻译：

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沙拉克果皮、果实和仁提取物的抗氧化、降血糖和抗高血压特性

Salak (Salacca zalacca) 是一种未被充分利用的水果。这种水果的生物活性很少被科学研究。因此，本研究旨在确定沙拉克果皮、果实和仁提取物的抗氧化活性，以及​​沙拉克果皮提取物的降血糖和抗高血压特性。使用蒸馏水、甲醇和乙醇提取 Salak。通过体外标准方法评估提取物的抗氧化活性、血管紧张素转化酶 (ACE) 和 α-淀粉酶抑制特性。此外，本研究还测定了提取物的总酚含量 (TPC) 和总黄酮含量 (TFC)。采用铁还原抗氧化能力（FRAP）和Trolox等效抗氧化能力（TEAC）方法测定了沙拉克提取物不同部位的抗氧化活性。通过DPPH测定计算自由基清除性能的百分比。分别使用 α-淀粉酶抑制和 ACE 测定评估 Salak 果皮的降血糖和抗高血压特性。发现 Salak 的甲醇中的水果提取物表现出最高的 TPC (10.27 ± 0.12 mg GAE/g)、TFC (11.04 ± 0.89 mg CE/g) 和所有样品的抗氧化特性，其中 TPC 和 TFC 与抗氧化活性密切相关。另一方面，蒸馏水提取的沙拉克内核显示出在所有沙拉克提取物中具有最低的 TPC (0.53 ± 0.05 mg GAE/g)、TFC (0.37 ± 0.01 mg CE/g) 和抗氧化性能。在目前的研究结果中，果皮提取物表现出与水果提取物相当的抗氧化活性。此外，果皮提取物表明无论使用何种溶剂，ACE 和 α-淀粉酶抑制活性都有一定程度的增强。甲醇和乙醇果皮提取物表明没有显着差异 (p < 0.05) ACE (98%) 和 α-淀粉酶 (90%) 抑制活性。然而，与甲醇和乙醇果皮提取物相比，蒸馏水提取的沙拉克果皮显示出显着较低的 ACE 和 α-淀粉酶抑制。目前的研究结果表明，沙拉克果的抗氧化性能最高，其次是果皮，最后是果仁，这显示了所有样品中最低的抗氧化性能。结果还表明，果皮提取物具有 ACE 和 α-淀粉酶抑制活性。