The Enigmatic Aliphatic Acetogenins and Their Correlations With Lipids During Seed Germination and Leaf Development of Avocado (Persea americana Mill.)

Abstract

Lipids in avocados have been widely studied due to their nutritional value and several reported bioactivities. Aliphatic acetogenins are a relevant component of the avocado lipidome and have been tested for several potential food and pharma industries applications. This work followed the evolution of avocado fatty acids (FAs) and aliphatic acetogenins during seed germination and leaf growth. Oil extracts of embryonic axes, cotyledons, and leaves from seedlings and trees were divided to analyze free acetylated acetogenins (AcO-acetogenins), and free FAs. Embryonic axes from germinating seeds contained the highest amount of AcO-acetogenins and FAs; this tissue also accumulated the most diverse FA profile with up to 22 detected moieties. Leaves presented the highest variations in AcO-acetogenin profiles during development, although leaves from seedlings accumulated the simplest FA profile with only 10 different FAs. Remarkably, AcO-acetogenins represented half of the carbons allocated to lipids in grown leaves, while embryonic axes and cotyledons always contained more carbons within FAs during germination. Thus, we hypothesized the use of the AcO-acetogenin acyl chain for energy production toward β-oxidation. Also, α-linolenic and docosahexaenoic acids (DHAs) were proposed as close AcO-acetogenin intermediaries based on a correlation network generated using all these data. Another part of the oil extract was fractionated into different lipid classes before transesterification to profile FAs and acetogenins bound to lipids. Acetogenin backbones were identified for the first time in triglycerides from cotyledons and mainly in polar lipids (which include phospholipids) in all developing avocado tissues analyzed. Seed tissues accumulated preferentially polar lipids during germination, while triglycerides were consumed in cotyledons. Seedling leaves contained minute amounts of triglycerides, and polar lipids increased as they developed. Results from this work suggest acetogenins might be part of the energy and signaling metabolisms, and possibly of membrane structures, underlining the yet to establish role(s) of these unusual lipids in the avocado plant physiology.

Looking into the lipid profile of avocado and byproducts: Using lipidomics to explore value‐added compounds

“…For instance, even when comparing the FA profile of avocado seed oil using different extraction techniques (SE vs. SCO 2 ), the MUFA 18:1 ω − 9 and the LA appears as the most abundant FAs, regardless of the method or extraction yield obtained (14% SE vs. 7% of SCO 2 ) (Páramos et al., 2020). Apart from LA, PUFA 18:3 ω − 3 is also found in high amounts in seed oil (10%–18%) (Table 8) (Colin‐Oviedo et al., 2022; Galvão et al., 2014; Páramos et al., 2020; Ramos‐Aguilar et al., 2021a; Wang et al., 2020).…”

“…Avocado byproducts are not considered oily. However, during fruit development, seeds accumulate oil up to 0.35% of their fresh weight, comprising ≈7% of oil content (Bora et al, 2001;Colin-Oviedo et al, 2022;Ge et al, 2018;Ge, Dong, et al, 2021;King-Loeza et al, 2023).…”

Emerging Plant Intoxications in Domestic Animals: A European Perspective

“…744–747). Persin is an acetogenin that is derived from the biosynthesis of long-chain fatty acids and possesses a structure similar to linoleic acid [ 75 ].…”