- Study of chemical composition of Syzygium myrsinifolium, Syzygium attopeuense, Syzygium antisepticum
 - Evaluation of Anti-inflammatory, α-Glucosidase, and α-Amylase Inhibitory activities

- Fourteen compounds (SM1-SM14) were isolated and their structures elucidated from the leaves of S. myrsinifolium. Among them were two new compounds, syzyfolium A (SM1) and syzyfolium B (SM2), along with twelve known compounds, including terminolic acid (SM3), actinidic acid (SM4), piscidinol A (SM5), threo-dihydroxydehydrodiconiferyl alcohol (SM6), lariciresinol-4-O-β-D-glucoside (SM7), icariol A2 (SM8), 14β,15β-dihydroxyklaineanone (SM9), garcimangosone D (SM10), (+)-catechin (SM11), myricetin-3-O-α-L-rhamnopyranoside (SM12), quercitrin (SM13), and 3, 4, 5-trimethoxyphenyl-(6ʹ-O-galloyl)-O-β-D-glucopyranoside (SM14).
- Ten compounds (SA1-SA10) were isolated and their structures elucidated from the fruits of S. attopeuense. These isolates comprised three new compounds: 2α,3β,6β-trihydroxy-24-nor-urs-4(23),12,20(30)-trien-28-oic acid 28-O-β-D-glucopyranoside (SA1), 3β,6β,23-trihydroxyurs-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (SA2), và (2R,3R)-5,7,3ʹ,4ʹ-tetrahydroxyflavanone 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (SA3). The remaining seven compounds were identified as centelloside C (SA4), syzygiumursanolide C (SA5), chebuloside II (SA6), quadranoside IV (SA7), epifriedelanol (SA8), friedelin (SA9), lupenyl acetate (SA10).
- Ten compounds (SAA1-SAA10) were isolated and characterized from the leaves of S. antisepticum. Among the isolated compounds were 3 new compounds: 2α,3β,20α,23-tetrahydroxy-nor-30-urs-12-en-28-oic acid 28-O-β-D-glucopyranoside (SAA1), 2α,3β,6β,23-tetrahydroxyoleana-11,13(18)-dien-28-oic acid (SAA2), and 4,6-dihydroxy-3-methyl-2-O-β-D-glucopyranosylbenzophenone (SAA3), and 7 known compounds: centelloside C (SAA4), syzygiumursanolide C (SAA5), chebuloside II (SAA6), quadranoside IV (SAA7), epifriedelanol (SAA8), friedelin (SAA9), lupenyl acetate (SAA10).
- All compounds isolated from S. myrsinifolium, S. attopeuense, and S. antisepticum were evaluated for anti-inflammatory activity by inhibiting NO production. The results indicated that the isolates from S. antisepticum exhibited moderate NO production inhibitory activity (IC50 ranging from 16.3 to 74.6μM), whereas those from S. myrsinifolium and S. attopeuense displayed weaker activity."
- All isolated compounds from S. myrsinifolium, S. attopeuense, and S. antisepticum were evaluated for their inhibitory activities against α-glucosidase and α-amylase. Compounds SM1 and SM2 exhibited potent α-amylase inhibitory activity with IC50 values of 35.48 and 43.60 μM, respectively, which were stronger than the positive control (IC50 = 144.54 μM). In addition, compounds SM3 and SAA9 displayed strong α-glucosidase inhibitory activity with IC50 values of 23.99 and 23.60 μM, respectively, both of which were more active than the positive control (IC50 = 46.80 μM).
Novelty and actuality and scientific meaningfulness of the results:
- Undescribed triterpenes syzyfolium A (SM1) and syzyfolium B (SM2) were isolated and their structures were determined from the leaves of S. myrsinifolium
- Three new compounds 2α,3β,6β-trihydroxy-24-nor-urs-4(23),12,20(30)-trien-28-oic acid 28-O-β-D-glucopyranoside (SA1), 3β,6β,23-trihydroxyurs-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (SA2), và (2R,3R)-5,7,3ʹ,4ʹ-tetrahydroxyflavanone 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (SA3) were isolated and structurally characterized from the fruits of S. attopeuense.
- Three previously unreported compounds, namely 2α,3β,20α,23-tetrahydroxy-nor-30-urs-12-en-28-oic acid 28-O-β-D-glucopyranoside (SAA1), 2α,3β,6β,23-tetrahydroxyoleana-11,13(18)-dien-28-oic acid (SAA2), and 4,6-dihydroxy-3-methyl-2-O-β-D-glucopyranosylbenzophenone (SAA3), were isolated from the leaves of S. attopeuense. Their chemical structures were elucidated by IR, HR-ESI-MS, 1D and 2D NMR spectra.

Excellent α-amylase inhibitory efficacy was noted for SM1 and SM2, while SM3 and SAA9 showed strong α-glucosidase inhibitory activity. This suggests that these compounds could play a significant role in the treatment of diabetes mellitus, which is consistent with previous reports on the uses of the folk medicinal plant. Therefore, these compounds should be studied further in vivo and included as potential drug leads for the supportive treatment of diabetes.