Novel cholinesterase inhibitory effect of α-spinasterol isolated from the leaves of Acacia auriculiformis A. CUNN Ex. Benth (Fabaceae)

Abstract

Purpose: To investigate the in vitro anticholinesterase, α-glucosidase and antioxidant activities of α-spinasterol isolated from Acacia auriculiformis leaves.Methods: The powdered leaves of Acacia auriculiformis were extracted with 70 % ethanol and the dried hydroalcoholic extract was suspended in water and partitioned with ethyl acetate and n-butanol to give their soluble fractions. The in vitro inhibitory activities of α-spinasterol were determined against cholinesterase and, α-glucosidase enzymes, and free radical scavenging potentials using (1,1-diphenyl-2-picrylhydarzyl (DPPH) and 2,2-azino-bis (3-Ethylbenzothiazoline-6-sulphonic acid (ABTS) antioxidantassays.Results: The compound, α-spinasterol, exhibited moderate anticholinesterase activity (IC50 value of 44.19±2.59 μg/mL which was significantly different at (p < 0.05) when compared to the standard galanthamine (IC50 value of 1.73 ± 1.10 μg/mL). It also displayed a good α-glucosidase inhibitory activity with IC``` value of 8.65 ± 1.71μg/mL which was not significantly different when compared to the standard, acarbose with IC50 value of 2.79±0.81 μg/mL. This compound, however, exhibited weak free radical scavenging activities at 26.93 ± 0.00 and 35.16 ±.0.26 % inhibition of DPPH+ and ABTS+ radicals as compared to ascorbic acid and Trolox (73.88 ± 0.04 and 99.82 ± 0.00%) respectively.Conclusion: The results show that α-spinasterol isolated from Acacia auriculiformis exerts potent inhibitory effect against cholinesterase enzyme which might serve as a lead in the search for drugs against Alzheimer disease and diabetes mellitus.
 Keywords: Acacia auriculiformis, α-Spinasterol, Galanthamine, Acarbose, Trolox, Ascorbic acid

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

“…Other miscellenous compounds ( Table S4 ) have equally shown interesting acetylcho-linesterase and butyrylcholinesterase inhibitory activities [ 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 ].…”

Pharmacology of α‐spinasterol, a phytosterol with nutraceutical values: A review

“…A recent study showed that α‐spinasterol could inhibit intestinal absorption of glucose. It inhibited the activity of α‐glucosidase with an IC 50 value of 8.6 μg/mL, which was not significantly different from that of the standard α‐glucosidase inhibitor, acarbose (Lawal et al, 2020). In the same study, α‐spinasterol was shown to moderately inhibit acetylcholine esterase.…”

“…In another report, dichloromethane extract of 233 g dry stem and 129 g dry root of Amaranthus viridis yielded 16 mg (0.007%) and 17 mg (0.013%) α‐spinasterol, respectively (Ragasa et al, 2015). In a recent study, about 10 mg α‐spinasterol (0.0025% W/W) was isolated from 408 g dry leaf powder of Acacia auriculiformis following 70% ethanol extraction (Lawal et al, 2020).…”

“…In the same study, α‐spinasterol was shown to moderately inhibit acetylcholine esterase. This might result in a moderate increase in the levels of acetylcholine in the blood (Lawal et al, 2020). Acetylcholine is known to stimulate muscarinic M3 receptors in pancreatic cells and augments insulin release (Liu, Wu, Liu, Yu, & Cheng, 2008).…”

“…In the same study, α-spinasterol was shown to moderately inhibit acetylcholine esterase. This might result in a moderate increase in the levels of acetylcholine in the blood (Lawal et al, 2020).…”