Senna alata, also known as Cassia alata (J. Ethnopharmacol. 2003;86:167-71), as well as Candle Bush and similar names such as Candelabra Bush, Empress Candle Plant, Candle Plant, and Candlewood Tree, among some others, is a tropical shrub that belongs to the Fabaceae family. Native to Central America and the Caribbean, S. alata has been introduced to many tropical countries and islands throughout the world.

Traditionally, the leaves of some Cassia species have been used topically to treat various viral skin conditions (Pharmacology 1980;20 [Suppl. 1]:104-12; Bone, K., Mills S., Principles and Practice of Phytotherapy: Modern Herbal Medicine. Principles of Herbal Pharmacology. London: Churchill Livingstone, 2000, p. 49). However, S. alata and its constituent sennosides are better known globally for conferring laxative activity than other medically beneficial properties. When taken internally, extracts of the botanical act as a laxative and diuretic and, when used externally, it is said to reduce pus and relieve inflammation (J. Ethnopharmacol. 1999;68:103-8).

This column will briefly discuss some of the recent promising research, as well as the geographical breadth of traditional medical applications of S. alata.

Antimicrobial Actions

In 2009, Chomnawang and associates investigated 17 Thai medicinal plants to ascertain their activity against methicillin-resistant Staphylococcus aureus (MRSA), and S. alata was found to be among those with the potential to inhibit the standard strain of S. aureus (Fitoterapia 2009;80:102-4).

Chomnawang et al. had previously examined the potential antimicrobial effects of other Thai medicinal plants against other bacterial species. In 2007, they focused on free radical-scavenging and cytokine-depleting properties of botanicals to determine their suitability as treatments for the inflammation provoked by the bacteria Propionibacterium acnes. Through 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and the nitroblue tetrazolium assay to identify antioxidant activity, the investigators determined that Garcinia mangostana demonstrated significant antioxidant activity, while Houttuynia cordata, Eupatorium odoratum, and S. alata exhibited moderate antioxidant activity. Extracts of S. alata also demonstrated a dose-dependent capacity to inhibit the production of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha (Fitoterapia 2007;78:401-8).

Actions Against Skin Pathogens

In 2005, Chomnawang et al. conducted a study to assess the antimicrobial properties of Thai medicinal plants against P. acnes and Staphylococcus epidermidis, two strains of bacteria that have been linked to the etiologic pathway of acne. With disk diffusion, they found that, among 13 plant species demonstrating the capacity to inhibit P. acnes growth, S. alata was one of four that exhibited strong inhibitory activity. In this and their subsequent studies, though, G. mangostana was shown to be the species displaying the broadest inhibitory and antimicrobial effects among Thai medicinal plants. Notably, S. alata did manifest encouraging antibacterial properties against S. epidermidis as well as P. acnes (J. Ethnopharmacol. 2005;101:330-3).

In 2003, ointments produced from ethanolic extracts of the leaves of S. alata, as well as Lantana camara and Mitracarpus scaber, were shown to be effective as topical treatments of bovine dermatophilosis (J. Ethnopharmacol. 2003;86:167-71).