Polyphenolic Compounds and Biological Activities of Leaves and Fruits of Syzygium samarangense cv. ‘Giant Green’ at Three Different Maturities

Abstract

Syzygium samarangense cv. ‘Giant Green’ is an underutilised fruit that can be found in Malaysia and other Asian countries. Since this fruit is not fully commercialised, the information about its potential health benefits is limited. Thus, this study was carried out to determine the polyphenolic contents (total phenolic and total flavonoid) and biological activities (antioxidant, alpha-glucosidase and antibacterial assay) of ‘Giant Green’ leaves and fruits at different maturity stages. The young, mature and old leaves, and unripe, half-ripened and ripened fruits were analysed. The results showed that the young leaves increased the TPC and TFC by 35% and 41%, over the old leaves. Similarly, TPC and TFC contents were 37% and 54% higher in unripe fruits compared to the ripened fruits. In addition, young leaves exhibited the strongest scavenging activity towards DPPH, NO and ABTS radicals with IC50 values increasing 1.6-fold, 1.7-fold and 2.3-fold, respectively, over the old leaves. However, in fruit samples, only unripe fruits were able to inhibit more than 50% of radicals. A comparable trend was observed in alpha-glucosidase inhibitory assay whereas young leaves and unripe fruits recorded 81% and 99% increases in IC50 values, respectively, from young leaves to old leaves and unripe fruits to ripened fruits. Identically, young leaves also showed a significant effect in antibacterial assay with an inhibition zone increase of 19%, 36%, 32%, and 31% in S. aureus, E. faecalis, S. typhimurium and E. coli, respectively, over the old leaves. However, only unripe fruits were most effective against all tested bacteria while half-ripened fruits were only effective against E. faecalis with a 1.1-fold increase in the inhibition zone compared to unripe fruits. Ripened fruits were resistant to all of the bacteria. These results suggest that the young leaves and unripe fruits of ‘Giant Green’ cultivar of S. samarangense could be a potential candidate for the management of some diseases coming from harmful free radicals or bacterial infection.

Discrimination of Syzygium samarangense cv. ‘Giant Green’ Leaves at Different Maturity Stages by FTIR and GCMS Fingerprinting

“…Horticulturae 2023, 9, x FOR PEER REVIEW 10 of 23 at three maturity stages were reported in our previous study [18]. As seen in the bi-plot (Figure 5C), most young leaf samples were located at the upper right-hand quadrant on the t1 axis.…”

“…PLS was established to investigate the relationship between bioactivities of antioxidants and alpha-glucosidase (Y variable) with FTIR fingerprint (x variable). The details about the antioxidant and alpha-glucosidase inhibitory activities of 'Giant Green' leaves at three maturity stages were reported in our previous study [18]. As seen in the bi-plot (Figure 5C), most young leaf samples were located at the upper right-hand quadrant on the t1 axis.…”

“…Horticulturae 2023, 9, x FOR PEER REVIEW 3 of 23 used in this study. The leaves were selected carefully based on the below picture (Figure 1) physical examination reported by our previous study [18].…”

Effects of Maturation on Antibacterial Properties of Vietnamese Mango (Mangifera indica) Leaves

“…In addition, the results also highlight young mango, characterized by a color ranging from dark reddish brown to light green, as the best materials to fight bacteria. Investigation into leaves of other herbal plants has also revealed similar results, showing that in the comparison with mature or old leaves, young leaves generally exhibit higher contents of bioactive compounds and produce stronger antibacterial effects [66]. However, in the case of mango leaves, relationships between maturity levels and therapeutic properties seem to be varied due to examined biological functions.…”

Integration of Horse Manure Vermicompost Doses and Arbuscular Mycorrhizal Fungi to Improve Fruit Quality, and Soil Fertility in Tomato Field Facing Drought Stress

“…Plants facing drought conditions and growing in an environment enriched with biostimulants/ organic fertilizers demonstrated an enhanced ability to cope with stress by activating antioxidants better than other plants. As shown in several studies, the accumulation of phenolic compounds is directly linked to improved DPPH activity in IC 50 plants [ 75 , 76 ]. This suggests that the increased accumulation of these compounds may be a contributing factor in improving the plant’s ability to regulate and suppress oxidative activities that can be harmful during periods of stress such as drought.…”