Diterpene Foliar Exudates of Blakiella bartsiifolia and Phytotoxicity of Clerodanes

Abstract

Blakiella bartsiifolia (S.F. Blake), an endemic and rare high altitude plant of the northern Andes, appears well adapted to the prevailing harsh environment owing in part to a thick glandular trichome cover. From foliar exudates, two new clerodanes, 15,16-epoxy-2-hydroxy-3,13(16),14-clerodatrien-20-oic acid (bartsiifolic acid) (2) and Z-15,16-dihydroxy-3,13-clerodien-20-oic acid (barthydrolic acid) (3), were isolated in addition to the known junceic acid (1). In addition, three new alicyclic furanoditerpenes: 1,20-epoxy-1,3(20),6(E),10(E),14-phytapentaen-18-methyl-19-oic acid (blakielic acid) (4), 1,20-epoxy-1,3(20),10(E),14-phytapentaen-18-methyl-19-oic acid (blakifolic acid) (5) and 1,20-epoxy-1,3(20),6,14-phytatetraen-19-methyl-18-oic acid (dihydrocentipedic acid) (6) were obtained in minor quantity. Seed germination and plantlet growth bioassays on Allium cepa and Lactuca sativa to monitor bioactivity during isolation procedures revealed compounds 1-3 with substantial inhibition comparable with synthetic linuron.

Recent advances in allelopathy for weed control: from knowledge to applications

“…Chlorodesmis fastigiata has recently been discovered to be a producer of linear diterpenes that act as anti‐algae agents . In relation to this, Rodriguez‐Hernandez et al isolated blakifolic, blakielic and dihydrocentipedic acids from Blakiella bartsiifolia in 2014 …”

“…118 In relation to this, Rodriguez-Hernandez et al isolated blakifolic, blakielic and dihydrocentipedic acids from Blakiella bartsiifolia in 2014. 119,120 Diterpenes can be found in fungi, 121 plants 122 or animals. 123 These compounds are often involved in defense mechanisms against pests and/or herbivores, as is the case for rhizathalene in Arabidopsis thaliana, 124,125 which serves as a signal for indirect defense by attracting parasitoids and predators of arthropod herbivores.…”