Bacopa monnieri (L.) Wettst.

‘B. monniera’, an erroneous name, which is not accepted by botanists but occurs frequently in the literature

Plantaginaceae (formerly Scrophulariaceae)

Bacopa; thyme-leafed gratiola; water hyssop

Aerial parts; dried whole plant

The active compounds are the dammarane triterpenoid saponins based on the bacogenins and jujubogenins, most notably the bacosides, bacopasides and bacosaponins (Chakravarty et al. 2001; Chakravarty et al. 2002). Older publications refer ‘bacosides A and B’, but ‘bacoside A’ has now been identified as a mixture of four saponins, bacoside A3, bacopaside II, bacopasaponin C and the jujobogenin isomer of the latter. The identity of ‘bacoside B’ still needs to be clarified, as there is contradictory information in the scientific literature (Deepak and Amit 2013). The herb also contains phenylethanoid glycosides including monnierisides I-III, the alkaloids brahmine and herpestine and cucurbitacin derivatives known as bacobitacins (Engels and Brinckmann 2011; Williamson et al. 2013).

Research on B. monnieri continues to deliver new insights, and although mainly positive, the evidence is not clear-cut. A systematic review of randomised controlled trials of B. monnieri extract on memory (Pase et al. 2012) included six studies using three different Bacopa extracts at doses of 300–450 mg extract per day. Across the studies, Bacopa improved performance on 9 of 17 tests in the domain of memory free recall, but the authors highlighted that there ‘were no cognitive tests in the areas of auditory perceptual abilities or idea production and only a paucity of research in the domains of reasoning, number facility and language behaviour’. Another meta-analysis (Kongkeaw et al. 2014) included nine studies with a chronic >12 weeks dosing of standardised extracts of B. monnieri without any co-medication and the authors concluded that B. monnieri improves cognition, particularly speed of attention.