Primin is a benzoquinone that has been found in P. obconica and has diverse biological activities.1,2,3,4 It selectively inhibits COX-2 over COX-1 (IC50s = 0.09 and 5.14 ?M, respectively) and induces the production of adrenochrome from epinephrine, a marker of pro-oxidant activity, in a cell-free assay when used at a concentration of 8.81 ?M.1 Primin is active against T. brucei rhodesiense and L. donovani (IC50s = 0.144 and 0.711 ?M, respectively), as well as S. aureus (IC50 = 8.94 ?M).2,3 In vivo, primin induces contact sensitization in guinea pigs.4
1.Landa, P., Kutil, Z., Temml, V., et al.Redox and non-redox mechanism of in vitro cyclooxygenase inhibition by natural quinonesPlanta Med.78(4)326-333(2011) 2.Tasdemir, D., Brun, R., Yardley, V., et al.Antituberculotic and antiprotozoal activities of primin, a natural benzoquinone: In vitro and in vivo studiesChem. Biodivers.3(11)1230-1237(2006) 3.Viegas, F.P.D., Espuri, P.F., Oliver, J.C., et al.Leishmanicidal and antimicrobial activity of primin and primin-containing extracts from Miconia willdenowiiFitoterapia138104297(2019) 4.Schulz, K.H., Garbe, I., Hausen, B.M., et al.The sensitizing capacity of naturally occurring quinones. Experimental studies in guinea pigs. II. BenzoquinonesArch. Dermatol. Res.264(3)275-286(1979)