In 2010, Shang et al. conducted multiple studies using A. scholaris. In the first published report, they assessed the anti-inflammatory and analgesic properties of the ethanolic leaf extract to validate its use in traditional Chinese medicine and modern clinical medicine. The investigators first determined that analgesic activity was conferred as the ethyl acetate and alkaloid fractions significantly diminished acetic acid-induced reactions in mice and, along with the ethanolic extract, reduced xylene-induced ear edema.
The researchers also performed in vivo and in vitro assessments of anti-inflammatory activity again on xylene-induced ear edema and carrageenan-induced air pouch formation in mice, as well as cyclooxygenase (COX)-1, -2 and 5-LOX inhibition.
In the air pouch model, A. scholaris alkaloids were found to have significantly spurred superoxide dismutase activity while lowering nitric oxide, prostaglandin E2, and malondialdehyde levels. In vitro tests, supporting evidence from animal models, showed that the three primary alkaloids isolated from A. scholaris leaves (picrinine, vallesamine, and scholaricine) inhibited the inflammatory mediators COX-1, COX-2, and 5-LOX. The researchers also noted that the in vitro anti-inflammatory assay results reinforced the notion of these alkaloids as the bioactive fraction of the plant (J. Ethnopharmacol. 2010;129:174-81).
In their second published report that year, Shang et al. investigated the antitussive and anti-asthmatic activities of the ethanolic extract, fractions, and chief alkaloids of A. scholaris leaf.
The researchers tested for antitussive effects using ammonia-induced or sulfur dioxide-induced coughing in mice and citric acid-induced coughing in guinea pigs. They evaluated anti-asthmatic activity via histamine-induced bronchoconstriction in guinea pigs. They also measured phenol red volume in murine tracheas to assess expectorant activity.
The data indicated antitussive activity, with significant alkaloid suppression of ammonia-induced coughing frequency in mice. Latency periods of sulfur dioxide-induced cough in mice and citric acid-induced cough in guinea pigs increased, and cough frequency in guinea pigs decreased.
Anti-asthmatic effects, such as suppression of convulsion, were observed in guinea pigs. In the expectorant assessment, tracheal phenol red production was increased. The researchers identified picrinine as the primary alkaloid responsible for these activities (J. Ethnopharmacol. 2010;129:293-8).
In addition, Jahan and Goyal showed that pretreatment with A. scholaris bark extract protected the bone marrow of mice against radiation-induced chromosomal damage and micronuclei induction (J Environ. Pathol. Toxicol. Oncol. 2010;29:101-11).
Conclusion
Despite the dearth of research on A. scholaris, the existing data are intriguing, particularly the findings that A. scholaris may have the capacity to amplify the anti-aging activity of retinoids while blunting their irritating effects. Although more research is needed to determine the dermatologic value of A. scholaris, the pursuit may potentially prove fruitful.
Dr. Baumann is in private practice in Miami Beach. She did not disclose any conflicts of interest. To respond to this column, or to suggest topics for future columns, write to her at sknews@elsevier.com.