Sceletium tortuosum

Sceletium tortuosum is not consumed as a food for macronutrient value; it is a succulent plant used as a psychoactive botanical preparation. Its relevance is entirely in its bioactive alkaloid profile rather than conventional nutritional content (negligible protein, fat, carbohydrate, and fiber contribution at typical doses of 25–50 mg standardized extract or 50–200 mg raw plant material). Key bioactive compounds: • Mesembrine (primary alkaloid, ~0.3–1.3% of dry plant weight depending on fermentation/preparation): Selective serotonin reuptake inhibitor (SRI) and potent phosphodiesterase-4 (PDE4) inhibitor; considered the principal anxiolytic and mood-enhancing constituent. Bioavailability is enhanced by traditional fermentation ('kougoed' process), which converts less active alkaloids into mesembrine-type compounds. • Mesembrenone (~0.1–0.5% dry weight): Dual SRI and PDE4 inhibitor; contributes to serotonergic activity; relative proportion increases in unfermented material. • Mesembrenol (trace to ~0.2%): Minor alkaloid with weaker SRI activity. • Mesembranol (trace to ~0.2%): Minor alkaloid contributing to overall pharmacological profile. • Δ7-Mesembrenone (variable trace amounts): Present in some chemotypes; biological activity less characterized. • Total mesembrine-type alkaloids in standardized commercial extracts (e.g., Zembrin®): Typically standardized to ≥0.35–0.40% total alkaloids, with defined ratios of mesembrine, mesembrenone, mesembrenol, and mesembranol. • Other constituents: Trace amounts of oxalic acid, flavonoids, and tannins are present in crude plant material but are not considered pharmacologically relevant at typical doses. Mineral/vitamin content: Not nutritionally significant at therapeutic doses (25–50 mg extract); no meaningful contribution of vitamins or minerals. Bioavailability notes: Oral bioavailability of mesembrine alkaloids appears adequate based on clinical efficacy at low doses (25 mg Zembrin® extract). Traditional fermentation (anaerobic curing for 2–8 days) significantly alters alkaloid ratios, increasing mesembrine relative to mesembrenone, and is believed to improve tolerability and potency. The alkaloids are lipophilic and likely undergo hepatic first-pass metabolism; sublingual or insufflation routes used traditionally may bypass first-pass effects and increase bioavailability, though clinical data is limited to oral dosing.