Fruit phenolics are important dietary antioxidant and antidiabetic constituents. The fruit parts (pulp, seed, seed coat, kernel) of underutilized indigenous six black jamun landraces (Syzygium cumini L.), found in Gir forest region of India and differed in their fruit size, shape and weight, are evaluated and correlated with antidiabetic, DPPH radical scavenging and phenolic constituents. The a-amylase inhibitors propose an efficient antidiabetic strategy and the levels of postprandial hyperglycemia were lowered by restraining starch breakdown. The sequential solvent systems with ascending polarity-petroleum ether, ethyl acetate, methanol and water were performed for soxhlet extraction by hot percolation method and extractive yield was found maximum with methanolic fruit part extracts of six landraces. The methanolic extracts of fruit parts also evidenced higher antidiabetic activity and hence utilized for further characterization. Among the six landraces, pulp and kernel of BJLR-6 (very small, oblong fruits) evidenced maximum 53.8 and 98.2% inhibition of a-amylase activity, respectively. The seed attained inhibitory activity mostly contributed by the kernel fraction. The inhibition of DPPH radical scavenging activity was positively correlated with phenol constituents. An HPLC-PDA technique was used to quantify the seven individual phenolics. The seed and kernel of BJLR-6 exhibited higher individual phenolics-gallic, catechin, ellagic, ferulic acids and quercetin, whereas pulp evidenced higher with gallic acid and catechin as a-amylase inhibitors. The IC 50 value indicates concentration of fruit extracts exhibiting C50% inhibition on porcine pancreatic a-amylase (PPA) activity. The kernel fraction of BJLR6 evidenced lowest (8.3 lg ml-1) IC 50 value followed by seed (12.9 lg ml-1), seed coat (50.8 lg ml-1) and pulp (270 lg ml-1). The seed and kernel of BJLR-6 inhibited PPA at much lower concentrations than standard acarbose (24.7 lg ml-1) considering good candidates for antidiabetic herbal formulations. Keywords Syzygium cumini L. Á Fruit parts Á a-Amylase inhibition Á Antioxidant activity Á HPLC profile Á Herbal formulation Abbreviations DPPH 1,1-diphenyl-2-picrylhydrazyl NIDDM Non-insulin dependent diabetes mellitus WHO World health organization BJLR Black jamun landraces HPLC High-performance liquid chromatography DNSA Di-nitro salicylic acid PDA Photodiode array 2FCRD Two factor complete block randomized design PPA Porcine pancreatic a-amylase IC 50 50% inhibition of enzyme activity Electronic supplementary material The online version of this article (

The indigenous black jamun landraces ( L.), found in western Gujarat of Gir forest region (India), produced fruits with different size and shape. Fruit morphology like shape, volume, weight, length, girth were examined and black jamun categorized into six landraces viz., BJLR 1 (big fruit, > 11 g); BJLR 2 (medium to big fruit, 8-11 g); BJLR 3 (medium fruit, 6-8 g); BJLR 4 (medium to small fruit, 5-6 g); BJLR 5 (small fruit, 3-5 g) and BJLR 6 (very small fruit, < 3 g fruit weight). The landraces (BJLR 1 and 2) with larger size fruits were accumulated higher amount of moisture, total fat content, sugars, total protein, starch, free amino acid contents. Smaller fruits (BJLR 6) contained higher amount of ascorbic acid-137 and 132 mg%; anthocynin-47.7 and 2.35 mg%; crude fibre 3.05 and 10.5 g%; and total phenol-21.7 and 45.0 mg g in their fruit pulp and seed part, respectively with better nutritional profile compared with big and moderate fruited landraces. Nutritional profile of six landraces indicated that fruit pulp accumulated higher amount of soluble sugars (6.51-17.6 mg g), anthocyanins (29.7-47.7 mg%) and free amino acids (7.54-18.9 mg%) while that of seeds exhibited higher amount of crude fibre (6017-10.5 g%), ascorbic acid (90-137 mg%), starch (22.8-29.4 g%), total protein (4.72-7.17 mg%), phenols (45-56.7 mg g). The black jamun landraces were subjected to ISSR based polymorphic finger prints and genetic diversity analysis. Total 144 bands were amplified across six landraces by 18 UBC primers, of which 94 were polymorphic with 64.2% average polymorphism. Cluster analysis demonstrates the BJLR 6 landraces distinguished from other landraces with 53% similarity.