Terpenoids from the whole plant of Vaccinium emarginatum Hayata and their anti-inflammatory activity

The metabolite characterization of the Vaccinium species have been well documented as rich sources of naturally occurring phytochemicals, which are represented by iridoids, steroids, terpenoids, coumarins, lignans, flavonoids, and anthocyanins, with promising bioactivities including antioxidative, anti-inflammatory, antinociceptive, antimicrobial, antidiabetic, and anticancer activity [1]. Vaccinium emarginatum Hayata (Ericaceae) is an endemic epiphytic shrub found at an altitude from 1,500 to 3,000 m in Taiwan. It has been used in folk medicine for treating cystitis, dysentery, enteritis, rheumatoid arthritis, and urinary tract infections in Taiwan. Its root nodules have been used as a Yang Tonic. In preliminary assessment, the in vitro anti-inflammatory activity against NO production of the V. emarginatum whole plant methanolic extract was mainly associated with its EtOAc-soluble fraction. The phytochemical investigation of this fraction afforded 2 new iridoids (1, 2), 22 pentacyclic triterpenoids including 2 new coumaroyl triterpenes (3, 4), and 4 steroids. Compounds 3 and 3β-O-trans-feruloyl-19α-hydroxyurs-12-en-28-oic acid (5) showed potent anti-inflammatory activity against NO production in LPS-induced RAW 264.7 cells [Tab. 1].

Tab. 1 Anti-inflammatory activity of compounds 1 and 3 against NO production in LPS-induced RAW 264.7 cells.

Compound	IC50 (μM)
3	12.36 ± 0.86
5	24.21 ± 1.28
Dexamethasone	1.52 ± 0.05

^a Values are expressed as mean ± SD of three independent experiments.

^b Dexamethasone was used as a positive control.

• References

• 1 Su Z. Anthocyanins and Flavonoids of Vaccinium L. Pharm Crop 2012; 3: 7-37