Major volatile and phenolic compounds in ‘kattekruid’ (Pseudodictamnus africanus), an important Cape herbal remedy

Abstract

Pseudodictamnus africanus (L.) Salmaki & Siadati [previously called Ballota africana (L.) Benth.] is a well-known Cape traditional medicine in many parts of the Cape region of South Africa. Known as kattekruid , it is used to treat various ailments, including respiratory infections, pain and inflammation. To date, only a single chemical compound, hispanolone, has been identified in the species. This study reports for the first time the major volatile and non-volatile compounds of kattekruid . Using GC–MS, 52 compounds could be identified in 12 samples of essential oil, of which viridiflorol (14.22 %), β-caryophyllene (7.65 %), and caryophyllene oxide (7.41 %) were consistently present as major compounds. Using multivariate statistics, chemophenetic variation was observed amongst the 12 samples collected from four populations used in the study. For example, one population has β-bisabolene (13.09 %) as a major compound, whereas another exhibited germacrene-D (6.87 %) and sesquiabene hydrate (5.30 %). Non-volatile constituents separated using LC–MS, were tentatively identified as (3) forsythoside B, (4) verbascoside/acetoside, (5) isoverbascoside, (12) ballotenol, (13) ballotenic acid and (25) hispanolone. This exploratory study provides the foundation for further, in-depth studies on chemical variation in the species. The reported anti-inflammatory activity of some of the major volatile and non-volatile compounds provides a potential rationale for the traditional medicinal uses that have been recorded. • First substantial study of volatile and non-volatile compounds. • Non-volatile compounds include forsythoside b and verbascoside. • Volatile compounds include viridiflorol, β-caryophyllene and caryophyllene oxide. • The major compounds have documented anti-inflammatory activity. • The traditional uses may be explained by the major compounds.