Boropinic acid is a prenyloxy-cinnamic acid recently isolated from Boronia pinnata Sm., an Australian shrub belonging to the family of Rutaceae [1]. Like other prenyloxy-cinnamic
and benzoic acids isolated from natural sources, few data about biological activity
have been reported in the literature. Boropinic and other natural prenyloxy-cinnamic
and benzoic acids, namely 4'-geranyloxy-p-coumaric acid, 4'-geranyloxy-ferulic acid, isolated from Acronychia baueri Schott [2], valencic acid, isolated from Citrus sinensis L. and Aegle marmelos Corr. [3] and 4-isopentenyloxy-vanillic acid, isolated from the liverwort Trichocolea lanata (Ehrh.) Dum. [4] were easily synthesized by a two-step sequence in high yield from
the corresponding p-hydroxy aromatic acid and were assayed for radical scavenging activity using the
DPPH test and for inhibition of enzymatic lipid peroxidation mediated by soybean 5-lipoxygenase.
Compared to other acids and to known antioxidant compounds like BHT, Trolox and ascorbic
acid, boropinic acid was by far more active in the lipoxygenase test (IC50=7.6 ng/mL, p<0.05). The inhibition value recorded suggested that boropinic acid acted
as an enzyme inhibitor rather than a mere radical or peroxide scavenger. This hypothesis
was confirmed by studying the interaction between boropinic acid and soybean 5-lipoxygenase
by molecular modeling techniques.
References: 1. Ito, C. et al. (2000), J. Nat. Prod. 63: 1344–1348. 2. Prager, R.H., Thredgold, H.M. (1966) Aust.
J. Chem. 19: 451–454. 3. Ali, M.S., Pervez, M.K. (2004), Nat. Prod. Res. 18: 141–146.
4. Perry, N.B. et al. (1996), J. Nat. Prod. 59: 729–33.
