Guava Leaf Extract Diminishes Hyperglycemia and Oxidative Stress, Prevents β-Cell Death, Inhibits Inflammation, and Regulates NF-kB Signaling Pathway in STZ Induced Diabetic Rats

Figure 1

(a) Total phenolic and flavonoid contents of guava leaf (dry weight basis) by using different solvent systems. (b) Quantification of phenolic compounds in guava leaf extracts by high performance liquid chromatography (HPLC). GA, gallic acid; PA, protocatechuic acid, THBA, 2,3,4-trihydroxybenzoic acid; DHBA, 3,4-dihydroxybenzaldehyde; HBA, 4-hydroxy benzoic acid; CA, chlorogenic acid; HDDBA, 4-hydroxy-3,5-dimethoxybenzoic acid; VNN, vanillin; PCA + SA, p-coumaric acid plus syringaldehyde; FA, ferulic acid; and SNA, sinapic acid. (c) HPLC chromatographs of phenolic compound standards (A) and guava leaf extracts (B): (1) gallic acid (GA), (2) protocatechuic acid (PA), (3) 2,3,4-trihydroxybenzoic acid (THBA), (4) 3,4-dihydroxybenzaldehyde (DHBA), (5) 4-hydroxybenzoic acid (HBA), (6) gentisic acid, (7) chlorogenic acid (CA), (8) vanillic acid (VA) plus caffeic acid (CAA), (9) 4-hydroxy-3,5-dimethoxybenzoic acid (HDDBA), (10) vanillin (VNN), (11) p-coumaric acid (PCA) + syringaldehyde (SA), (12) ferulic acid (FA), (13) sinapic acid (SNA), and (14) salicylic acid (SAL). (d) Possible phenolic compounds identified in guava leaf extract. (1) Gallic acid (GA), (2) protocatechuic acid (PA), (3) 2,3,4-trihydroxybenzoic acid (THBA); (4) 3,4-dihydroxybenzaldehyde (DHBA), (5) 4-hydroxybenzoic acid (HBA), (6) gentisic acid, chlorogenic acid (CA), (7) 4-hydroxy-3,5-dimethoxybenzoic acid (HDDBA), (8) vanillin (VNN), (9) and (10) p-coumaric acid (PCA) + syringaldehyde (SA), (11) ferulic acid (FA), and (12) sinapic acid (SNA).

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