Byrsonic Acid—the Clue to Floral Mimicry Involving Oil-Producing Flowers and Oil-Collecting Bees

Abstract

Tetrapedia diversipes and other Apidae (Anthophoridae) may be deceived by floral similarities between Malpighiaceae and Orchidaceae of the Oncidiinae subtribe. The latter do not usually exudate floral oils. Thus, visitors may pollinate the flowers in a deceit/food/pollination syndrome. We studied the chemical compositions of Byrsonima intermedia (Malpighiaceae) floral oil and T. diversipes (Anthophoridae) cell provisions. From B. intermedia floral oil, we isolated a novel fatty acid (3R, 7R)-3,7-diacetoxy-docosanoic acid, here named byrsonic acid, and from T diversipes cell provisions we isolated two novel fatty acid derivatives 3,7-dihydroxy-eicosanoic acid and 3,7-dihydroxy-docosanoic acid, here named tetrapedic acids A and B, respectively. The three fatty acid derivatives have common features: possess long chains (20 or 22 carbon atoms) with no double bond and either hydroxy or acetoxy groups at carbons 3 and 7. This characteristic was also encountered in the fatty acid moiety of oncidinol (2S, 3'R, 7'R)-l-acetyl-2-[3', 7'-diacetoxyeicosanyl)-glycerol, a major floral oil constituent of several Oncidiinae species (Orchidaceae). Thus, both tetrapedic A (C20) and B (C22) could be the biotransformation products of oncidinol and byrsonic acid by T. diversipes hydrolases. These are the chemical clues for bee visitation and oil collecting from both plant species. The results indicate that the deceit/pollination syndrome should not be applied to all Oncidiinae flowers.

Biotic Resource Needs of Specialist Orchid Pollinators

“…Mullerian mimicry is probably involved in these orchids and the Malpighiaceous species they resemble (Silvera, 2002), an idea supported by similarity in chemical components in the floral oils of Byrsonima intermedia Ad. Jussieu and some oil-reward Oncidium species (Reis et al, 2007). These neotropical orchid-oil-reward flower systems could involve large numbers of orchids because there are ca.…”

Constituintes químicos e atividade antioxidante de Byrsonima gardneriana (Malpighiaceae)

“…Este óleo floral é rico em ácidos graxos livres e o principal constituinte identificado foi o ácido birsônico. 6 O gênero Byrsonima é composto por cerca de 150 espécies e encontrado principalmente a partir do México, difundindo-se por toda América do Sul. 5 No Brasil são encontradas no norte, nordeste e região central, podendo também ser encontradas em regiões serranas do Sudeste.…”

“…17 A referida espécie não apresenta estudos sobre seus constituintes químicos descritos na literatura, destacando-se a importância de um estudo fitoquímico criterioso da mesma. Neste artigo reportamos o isolamento e a caracterização estrutural de cinco triterpenos, 3-oxo-5-ene-glutinona (1), taraxerona (2), friedelina (3), lupeol (4) e β-amirina (5), um flavonoide, (+)-catequina (6). A atividade antioxidante do extrato etanólico bruto e das fases hexânica, clorofórmica, acetato de etila e n-butanólica também foi avaliada.…”

Non-volatile floral oils of Diascia spp. (Scrophulariaceae)

“…Our group was first to report partially acetylated 3,7-dihydroxy fatty acids as a new type of constituent in Malpighia coccigera (Malpighiaceae) oil; and to discuss a possible relationship between floral oil and plant epicuticular wax biosynthesis. Recently, Reis et al (2007) proved R configuration for both positions 3 and 7.…”