Antioxidant and antibacterial properties of guava leaf extracts as affected by solvents used for prior dechlorophyllization

Abstract

The impacts of different solvents used for removing chlorophyll in guava leaf powder on antioxidant and antibacterial properties of resulting ethanolic extracts were studied. Among all solvents, acetone was the most effective in chlorophyll removal, followed by chloroform as indicated by the lowest chlorophyll a and b contents in resulting extract. However, the ethanolic extract from leaf powder dechlorophyllized using acetone (ACE) showed the lowest antioxidant activities, except for H2O2 scavenging activities (744.12 µmol TE/g), which exhibited the highest value (p < 0.05). Extract from chloroform dechlorophyllized leaf powder (CHL) had the highest antioxidant activities (240.78, 2327.42, and 2598.41 µmol TE/g for DPPH, ABTS, and FRAP assays, respectively), compared to other extracts. For antibacterial activity, ACE had the highest MIC (≥2.5 mg/mL) and MBC (≥5 mg/mL) against all tested microorganisms (p < 0.05). Chloroform was the appropriate solvent for dechlorophyllization, and the resulting extract had higher antioxidant and antibacterial properties than others. Practical applications Oxidative processes and microbial spoilage are responsible for deterioration and safety of perishable food. Phenolic compounds extracted from plant materials are gaining more attention because of their remarkable antioxidant and antibacterial properties. Plant extracts can serve as a natural additive that can replace synthetic chemical additives in foods. However, the application of ethanolic plant extract in food is limited because of their characteristic green color. Dechlorophyllization of leaf extract before extraction could be a means for eliminating this limitation. To the best of our knowledge, this is the first report on the effect of solvents used in dechlorophyllization of leaf powder on the antioxidant and antibacterial properties of their resulting extract. The provided information would serve as background knowledge for preparing the plant extracts without discoloration problem. As a consequence, wider use of leaf extracts can be achieved.

Natural Preservatives for Extending the Shelf‐Life of Seafood: A Revisit

“…Drying, grinding, or size reduction of the plant materials and, sometimes, dechlorophyllization, depending on the plant material, are the major processes in the pre-extraction stage (Azwanida, 2015;Chotphruethipong, Benjakul, & Kijroongrojana, 2017). Olatunde, Benjakul, and Kitiya (2018) demonstrated that solvents have a profound role in dechlorophyllization of guava leaf, in which the ethanolic extract from chloroform-dechlorophyllized leaf powder showed the highest antioxidant efficacy. However, the extract of leaves dechlorophyllized with acetone had very low yield.…”

Evaluation of the impact of chlorophyll removal techniques on polyphenols in rosemary and thyme by‐products

“…However, these processes are not entirely selective and can result in a reduction in the levels of the compounds with technological capacities in the decolorized extracts (Berdahl & McKeague, ). Different organic solvents (acetone, methanol, propanol, and chloroform) have also been assessed for eliminating chlorophyll from ethanolic extracts of guava leaf powder (Olatunde, Benjakul, & Vongkamjan, ). This study showed that nonpolar solvents such as chloroform were suitable for chlorophyll removal and maintained the antioxidant and antibacterial potentials of the extracts, while polar solvents (methanol, propanol, and acetone) resulted in reduction of both the antioxidant and antimicrobial activities (Olatunde et al, ).…”

“…Different organic solvents (acetone, methanol, propanol, and chloroform) have also been assessed for eliminating chlorophyll from ethanolic extracts of guava leaf powder (Olatunde, Benjakul, & Vongkamjan, ). This study showed that nonpolar solvents such as chloroform were suitable for chlorophyll removal and maintained the antioxidant and antibacterial potentials of the extracts, while polar solvents (methanol, propanol, and acetone) resulted in reduction of both the antioxidant and antimicrobial activities (Olatunde et al, ). Hence, decolorization constitutes a significant potential hurdle in the production and the subsequent applicability of plant extracts from herbs and their by‐products in food formulations.…”

Dielectric barrier discharge cold atmospheric plasma: Bacterial inactivation mechanism

“…Han et al (2016) and Lu, Patil, Keener, Cullen, and Bourke (2014) documented that the mode of bacterial inactivation by plasma generated using atmospheric air varied with the type of bacteria. GPB are more resilient to antimicrobial agent treatment, which is attributed to their cell wall containing several layers of peptidoglycan in comparison with GNB with single layer of peptidoglycan and several layers of lipopolysaccharide (Olatunde, Benjakul, & Vongkamjan, 2018, 2019c.…”