Subclass of Terpenoids

Diterpenes

Twenty-carbon terpenes, including potent actives like forskolin and the sweet steviol glycosides.

Overview

About Diterpenes

Diterpenes are the twenty-carbon terpenes, built from four isoprene units. At this size volatility is largely gone — these are resin and latex compounds rather than essential-oil aromatics, and they are recovered by solvent extraction rather than distillation.

The group has an unusually wide pharmacological range. It contains some of the gentlest sweeteners in the plant kingdom and some of the harshest irritants, with little to warn you which is which from the class name alone.

Where Diterpenes Occur

Conifer resins and the latex-bearing families are the classic sources, alongside a scattering of specialist herbs:

Conifers

abietic and pimaric resin acids

Stevia

the steviol glycosides

Coleus (Plectranthus barbatus)

forskolin

Rosemary and sage

carnosic acid and carnosol

Ginkgo

the ginkgolides

Spurge family (Euphorbiaceae)

phorbol esters and relatives

Pharmacological Importance

Several diterpenes are precise molecular tools rather than diffuse plant actives. Forskolin directly activates adenylate cyclase, raising intracellular cAMP — a mechanism specific enough that it is a standard laboratory reagent. The ginkgolides are selective platelet-activating-factor antagonists. Steviol glycosides bind sweet-taste receptors at up to 300 times the potency of sugar while contributing no calories.

The rosemary diterpene phenols carnosic acid and carnosol take a different route again, acting as Nrf2 activators and lipid-phase antioxidants — which is why standardized rosemary extract is an approved food preservative.

Toxicity & Safety

Class-level generalizations fail here more than anywhere else in the terpenoids. Steviol glycosides have been through full food-additive safety review; ginkgolides and forskolin are used at supplement doses with a reasonable record.

At the other end, the phorbol esters and daphnane diterpenes of the spurge and mezereon families are severe skin and mucosal irritants and tumour promoters, and several are the reason those plants are handled with gloves. Judge diterpenes one compound at a time.

Constituents

All Diterpenes

97 total Filter diterpenes

10-Deacetylbaccatin III 1 herb 14-Deoxy-11,12-didehydroandrographolide 1 herb 7-alpha-Acetoxymarrubiin 1 herb

Abietic acid 9 herbs Acanthoic Acid 1 herb Alpha-resinic acid 1 herb Andrographiside 1 herb Andrographolide 1 herb Austroinulin 1 herb

Ballotenol 1 herb Ballotinone 1 herb

Cafestol 1 herb Carnosic acid 3 herbs Carnosol 2 herbs Cleroda-7,14-dien-13-ol 1 herb Clerodane diterpenes 1 herb Communic acid 1 herb Cryptotanshinone 1 herb Cyathane diterpenoids 1 herb

Dehydroabietic acid 3 herbs Deoxyandrographolide 1 herb Dihydrotanshinone I 1 herb Diterpene alcohols 1 herb Diterpene diketones 1 herb

Open in filterable index

Source Plants

Herbs Containing Diterpenes

32 herbs

Plants in the materia medica documented to carry diterpenes, with the compounds each one is listed for. The bar counts how many DISTINCT diterpenes are on record for a plant, relative to the best-documented — it measures breadth of record, not potency, so a plant with one well-studied compound can outrank a richer source that has simply been analysed less. Where a measured concentration is on record it is quoted inline; most entries have none yet.