Asiatic pennywort

Asiatic pennywort (Centella asiatica) is a perennial creeping herb that hugs the ground and roots at the nodes; its stems are 5–20 cm long but can reach about 1 m. The leaves are kidney-shaped to almost round, 0.8–9 cm across, cordate at the base and crenate at the margin, on highly variable petioles; small greenish to pale-purple flowers form almost head-like umbels near the ground, and the flattened fruit is 3–4 mm with prominent ribs. The plant favours moist places — damp grassland along rivers, pond edges, swamps and forest clearings — and according to the Flora of Tropical East Africa grows from near sea level up to about 3,480 m.

Asiatic pennywort is widespread throughout the tropics and extends into the subtropics: Asia, Africa, Oceania, and naturalised in the Americas. According to Kew POWO the species is native to the humid tropics of the Old World and is widely cultivated and used in South Asia (gotu kola in India and Sri Lanka), Southeast Asia (Vietnam, Thailand) and China. Because runners root readily at the nodes, it quickly forms mats and tolerates many moist, organic-rich soils.

The main actives are pentacyclic triterpene saponins (triterpenoids), typically about 1–8% of the dried herb, built around four marker compounds: asiaticoside, madecassoside, asiatic acid and madecassic acid. Asiaticoside and madecassoside are the glycosides thought to drive wound healing and collagen synthesis, while asiatic acid and madecassic acid are the antioxidant, anti-inflammatory aglycones. Pennywort also contains brahmoside, brahminoside, flavonoids, carotenoids, volatile oil and minerals.

Pennywort is both a medicine and a familiar vegetable: young leaves are eaten raw or juiced, and in Indian traditional medicine (gotu kola) and Vietnamese practice it is used as a mild calmative, a circulation tonic and a wound healer. On clinical evidence, the systematic review by Arribas-López et al. (Int. J. Environ. Res. Public Health, 2022), covering four clinical trials, found that C. asiatica may improve wound contraction, re-epithelialisation and wound appearance; a double-blind trial in acne patients using a standardised ECa 233 gel (53.1% madecassoside, 32.2% asiaticoside) reported reduced skin inflammation. Reviews in Pharmaceutics (2024) and the Journal of Cellular and Molecular Medicine (Bandopadhyay et al., 2023) summarise how asiaticoside and madecassoside raise type I collagen synthesis, modulate inflammation and act as antioxidants.

Pennywort is generally considered safe at usual doses; some people may experience drowsiness, headache, dizziness or skin allergy when applied topically, so caution is advised with sedatives, sleeping aids or liver-metabolised drugs. For conservation, the IUCN lists Centella asiatica as Least Concern (LC; Red List species 168725) and an extinction-risk prediction model (Bachman et al., 2024) confirms it is not threatened. The species grows wild and is cultivated; the main pressures are over-collection and agricultural herbicides.