The Mastic Tree (Pistacia lentiscus L.) Leaves as Source of BACs: Effect of Growing Location, Phenological Stage and Extraction Solvent on Phenolic Content

Abstract

Research background. Mastic tree (Pistacia lentiscus L.) of the Anacardiaceae family is an evergreen shrub from Mediterranean countries where it is used in traditional medicine. Analysis of P. lentiscus leaf, stem, fruit and root extracts showed high concentrations of principal groups of secondary metabolites (flavonoids, phenolic acids and tannins), suggesting the plant possesses great biological potential. Therefore, the aim of this research is to evaluate the impact of environmental parameters and the extraction solvent type on the concentration of phenols in mastic tree leaf extracts grown at four different locations along the Adriatic coast (Barbariga, Lun, Hvar and Vela Luka) during three phenological stages (early flowering, early fruiting and late fruiting). Experimental approach. Since mastic tree plant has phenolic compounds with different structures and chemical properties, ethanolic and methanolic leaf extracts were analysed using high-performance liquid chromatography (HPLC) coupled with UV/Vis PDA detector. Phenolic compounds were identified by comparing the retention times and spectral data with those of standards at 280 and 340 nm. Results and conclusions. In all samples, phenolic acids and flavonol glycosides were quantified, while catechin was quantified only in methanolic extracts. The 5-O-galloylquinic acid was determined as a predominant phenolic compound in all samples followed by monogalloyl glucose, 3,5-di-O-galloylquinic acid, 3,4,5-tri-O-galloylquinic acid and gallic acid, respectively. Myricetin-3-O-rhamnoside was found to be the predominant flavonol glycoside followed by myricetin-3-O-glucoside, myricetin-3-O-glucuronide, quercetin-3-O-rhamnoside and derivative of flavonol glycoside. The mass concentration of these compounds significantly varied during different phenological stages, at different growing locations and used extraction solvents. The highest phenolic mass concentration was determined in the samples harvested at Hvar growing location and extracted in 80 % methanol. The highest total phenolic acid mass concentration was obtained in the samples harvested during the flowering phenological stage and the highest total flavonoid mass concentration in the samples harvested during the early fruiting stage. Novelty and scientific contribution. The obtained data provide a better understanding of the P. lentiscus species phenolic concentration, which can lead to further investigations regarding the valorisation of mastic tree leaves as pharmaceutical products or as food products with added value.

Effects of Harvesting Time on Tannin Biological Activity in Sambiloto (Andrographis paniculata) Leaves and In vitro Diet Digestibility Supplemented with Sambiloto Leaves

“…Similarly, the values for total phenols compounds (11.62 -12.45 mg/g) in A. paniculata leaves reported by Nagajothi et al (2018) were lower compared to our study. Variations in phenolic concentrations depend on specific agro-ecosystem conditions such as temperature, altitude and precipitation (Dragović et al, 2020). Naumann et al (2018) Our study demonstrated that there are no significant effect on total phenols concentration (mg/g) in A. paniculata leaves between two harvesting stages.…”

“…Besides, Ahmed et al (2020) also showed that the content of phenolic compounds was associated with maturity stages in Citrus paradise fruits. The difference in results may be due to the different climatic and environmental conditions, pre-and post-harvest factors such as species and cultivars and technical conditions (storage, drying process, transportation and extraction method) (Dragović et al, 2020;Kamaruzaman et al, 2020;Engin and Mert, 2020).…”

“…This may be due to the natural mechanisms of plant protection. In plant defense mechanism, the production of secondary metabolites such as phenolic and tannin increases to protect the maturation process of grain (Dragović et al, 2020;Wahyono, Astuti, et al, 2019). Phenolic contents (condensed tannin and phenolic acid) of persimmon leaves were significantly related to their antioxidant activities (Chang et al, 2019).…”

Vaccinium vitis-idaea L. Fruits: Chromatographic Analysis of Seasonal and Geographical Variation in Bioactive Compounds

“…Plants are exposed to substantial phenological variations, including environmental and seasonal fluctuations over the course of the year [2]. Although the metabolic processes leading to the accumulation of bioactive constituents are basically controlled by genetic makeup, physiological conditions and harvesting time are key essential factors that influence bioactive compounds contents in different organs of medicinal plants [3][4][5]. Great variability in phytochemical composition and quantity could also be attributed to plant geographical origin and edaphic factors [6].…”

“…Plants have cells known as circadian clock genes, and thus are able to anticipate seasonal changes and adapt to different growing conditions by regulating the development and accumulation of bioactive compounds in the presence of any external or environmental cues [7]. Relations among the accumulation and storage of secondary plant metabolites due to abiotic stresses have not yet been fully defined, and effects are likely to vary depending on the plant, organ, and type of metabolites [3]. Therefore, it is of great importance from the plant material quality point of view to study relations of growth conditions and chemical composition of edible plants.…”