Bioactive characterization of Persea americana Mill. by-products: A rich source of inherent antioxidants

Abstract

A B S T R A C TAvocado (Persea americana Mill.) is a worldwide consumed fruit, with great interest for cosmetic and pharmaceutical industries; however, 30% of avocado fruits are bio-wastes (peels and kernels), converting them into a potential source of bioactive compounds, such as phenolic compounds. Therefore, the hydroethanolic extracts of peels and kernels of Persea america Mill. var. Hass were analysed regarding their individual phenolic profile by HPLC-DAD/ESI-MS and correlated with their antioxidant, antimicrobial and cytotoxic activities. Avocado byproducts presented a very distinct phenolic profile, presenting higher concentration in peels (227.9 mg/g of extract for total phenolic content), mainly in (epi)catechin derivatives (175 mg/g of extract), followed by chlorogenic derivatives (42.9 mg/g of extract). In this study hydrophilic and lipophilic antioxidant assays were performed together for the first time in P. americana by-products, and although kernels showed a great antioxidant potential (EC 50 values ranging from 18.1 to 276 μg/mL), peels presented the highest potential (EC 50 ranging from 11.7 to 152 μg/mL), mainly due to the presence of phenolic compounds, and an overall better performance in the antibacterial assays. Further studies needs to be conducted to better understand the correlation between the presence of phenolic compounds and bioactivities, however, the main objective is to implement these biocompounds in different products and industries, due to results obtained, P. americana peels could be a great alternative in the substitution of synthetic antioxidants.

Improvement of the polyphenol extraction from avocado peel by assisted ultrasound and microwaves

“…(>1,000 μg/mL). The antimicrobial activity is also in line with the MIC values reported previously (Melgar et al, ; Raymond Chia & Dykes, ). Despite it, the MIC for S. aureus and E. coli in this study was lower.…”

“…In some cases, ultrasonic waves modify and degrade the flavonoids decreasing its activity (Chowdhury & Viraraghavan, ). The TPC from DE here reported agreed with Melgar et al (), which extraction was performed with ethanol/water (80:20, v/v), after 1 hr of stirring (125 rpm) at room temperature in two cycles. The latter authors reported 227.9 mg GAE/g, albeit, for the best of our knowledge, the TPC obtained from the combined method in this study is superior to the rest of the recent related reports.…”

“…While MAE and UAE did not show significant differences ( p > .05) between the antioxidant indicators; maceration presented the lower FRAP, but the lipidic peroxidation inhibition was statistically equal ( p > .05) to UAE and MAE. Even though this is the first work reporting the comparison of different extraction methods on the biological activity of avocado peel phenolic extracts; the results are in good agreement with Tremocoldi et al (), Melgar et al () and Morais et al (), whereas, the antioxidant indicators here, were entirely satisfactory.…”

“…Avocado peel is a rich source of biologically active polyphenols. From the 3.8 million tons of the actual production of avocado, the Hass variety is the furthermost industrialized (Melgar et al, ). Consequently, generates large quantities of by‐products (peel and seed), which usually are considered as waste (Hernández‐López, Rodríguez‐Carpena, Lemus‐Flores, Grageola‐Nuñez, & Estévez, ; Rodríguez‐Carpena, Morcuende, Andrade, Kylli, & Estévez, ).…”

“…Phenolics from avocado by‐products have been obtained conventionally and less affordable. The recent studies about phenolic extraction from avocado by‐products employed the conventional maceration (Melgar et al, ; Torres et al, ) or less affordable non‐conventional methods (Figueroa, Borrás‐Linares, Lozano‐Sánchez, & Segura‐Carretero, ). Regarding UAE, it was performed in another study to characterize the phytochemicals of two varieties of avocado fruits and their by‐products (Tremocoldi et al, ).…”