Inhibitors of Xanthine Oxidase and Scavengers of Superoxide Anions from <I>Cryptolepis sanguinolenta</I> (Lindl.) Schlechter (Periplocaceae)

Abstract

Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae) is a medicinal plant used in some African countries against infectious and parasitic diseases. Six of its constituent alkaloids have been isolated from the root bark, identified spectroscopically as cryptoquindolinine (1), quindoline (2), neocryptolepine (3), cryptolepine (4), 11‐hydroxycryptolepine (5) and biscryptolepine (6), and their interaction with the xanthine‐xanthine oxidase enzyme system has been tested. Compound 5 has been shown to inhibit xanthine oxidase and act as a scavenger of superoxide anions. Alkaloids 1–4 and 6 were devoid of effect in both assays at the highest test concentration of 100 mM. These findings suggest the importance, in the manifestation of both activities, of the hydroxyl group present in 5 but not in the other alkaloids.

Phytochemical and Pharmacological Review of Cryptolepis sanguinolenta (Lindl.) Schlechter

“…The authors reported a decrease in plasma urea levels and elevation in plasma creatinine associated with diabetes mellitus. Similar to the reports by Cimanga et al [ 88 ], it was identified that cryptolepine reversed diabetes-associated elevation of plasma cholesterol, triglycerides, and low-density lipoproteins, with reduction in high-density lipoproteins. Cryptolepine exhibited dose-dependent regeneration of β -islet cells; however, it could not repair degenerated liver and kidney tissues.…”

“…Cimanga and his team [ 88 ] investigated the effects of C. sanguinolenta -isolated alkaloids on xanthine oxidase and the production of superoxide anions. From the results of the study, it was shown that cryptoquindoline, quindoline, cryptolepine, neocryptolepine, and biscryptolepine were devoid of effects on xanthine oxidase activity with no recognizable activity against superoxide anion production.…”

“…However, 11-hydroxycryptolepine was identified to exhibit significant inhibition of xanthine oxidase and the production of superoxide anions. With 11-hydroxycryptolepine having a distinctive hydroxyl group as opposed to the other alkaloids, it is suggested that the presence of a hydroxyl group is important for the inhibition of xanthine oxidase and the production of superoxide radicals [ 88 ].…”

Indoloquinolines as Scaffolds for Drug Discovery

“…However, quercetin a flavonol used as reference was more active (IC 50 of 2.62 and 3.4 mM, respectively) than C. sanguinolenta alkaloids [140]. It was concluded that inhibition of the superoxide anions does not seem be the mechanism responsible for the anti-inflammatory activity of these indoloquinolines, being perhaps the reported antagonizing prostaglandin effects the ones responsible for the activity.…”

“…12) [140]. During inflammation reactive oxygen species arising from the phagocytic cells are produced and the presence of these species attracts more phagocytic cells, aggravating the inflammatory response.…”