BACKGROUND: Aging is an inevitable process for all living organisms. During this process reactive oxygen species
generation is increased which leads to the activation of hyaluronidase, collagenase and elastase, which can further
contribute to skin aging. Four southern African medicinal plants; Clerodendrum glabrum, Schotia brachypetala,
Psychotria capensis and Peltophorum africanum, were investigated to assess their anti-aging properties.
METHODS: Anti-elastase, anti-collagenase and anti-hyaluronidase activities of twenty-eight samples, consisting of
methanol and ethyl acetate extracts of the four plants, were determined using spectrophotometric methods. Radical
scavenging activity was determined by the ability of the plant extracts to scavenge the ABTS•+ radical.
RESULTS: The majority of the samples in the anti-elastase assay and nine in the anti-collagenase assay showed more
than 80% inhibition. The ethyl acetate extract of S. brachypetala bark and leaves of P. capensis inhibited elastase
activity by more than 90%. The methanol extract of S. brachypetala bark contained the highest anti-hyaluronidase activity
(75.13 ± 7.49%) whilst the ethyl acetate extract of P. africanum bark exhibited the highest antioxidant activity
(IC50: 1.99 ± 0.23 μg/ml).
CONCLUSION: The free radical scavenging activity and enzyme inhibitory activity of the plant extracts investigated
suggests that they can help restore skin elasticity and thereby slow the wrinkling process. P. africanum was the plant
with the most promising activity and will be subjected to further testing and isolation of the active compound/s.