HPLC phytochemical profiling, antioxidant activity and in vitro evaluation of inhibitory effects of Terminalia catappa stem bark extract on enzymes linked to diabetes, hypertensive vasoconstriction and erectile dysfunction

Abstract

Background

Terminalia catappa is a traditional medicinal plant used for several ailments among the local folks. Among the locals, the stem bark is an important constituent of polyherbal remedies for the treatment of cancer and metabolic diseases; however, there is a paucity of scientific reports on it. This study aimed to evaluate the in vitro antidiabetic, antihypertensive and antierectile dysfunction effects of Terminalia catappa stem bark extract (TSBE).

Methods

The HPLC phytochemical profiling, total phenol content, total flavonoid content and antioxidant capacity of the extract were delineated. The inhibitory effects of TSBE on activities of α-glucosidase, α-amylase, acetylcholinesterase (AChE), arginase, phosphodiesterase-5′ (PDE-5′), angiotensin-converting enzyme (ACE) and ecto-5 nucleotidase (Ecto-5-NTD) were estimated following standard procedures.

Results

HPLC of TSBE profiled ferulic acid, gallic acid, caffeic acid, catechin, rutin, p-coumaric acid, chlorogenic acid, kaempferol, apiginin and quercetin. TSBE had IC₅₀ values of 49.19 µg/mL and 55.42 µg/mL in terms of scavenging DPPH and NO radicals, respectively. The TSBE inhibited α-glucosidase and α-amylase activities with IC₅₀ values of 71.53 µg/mL and 105.11 µg/mL, respectively. The inhibitory effects of TSBE on AChE, arginase, PDE-5′, and ACE revealed IC₅₀ values higher than that of standards. TSBE demonstrated a stimulatory effect on ecto-5-NTD activity.

Conclusion

TSBE revealed promising antioxidant, antidiabetic, antihypertensive and antierectile dysfunction (anti-ED) properties which may be associated with the bioactive compounds present in the extract.