The Bioactive Composition, Antioxidant, and Antimicrobial Properties of Pink-Purple Edible Flowers in Thailand

Supaporn Pumriw; Boonyote Kamjijam; Jintana Sangsopha; Thorung  Pranil

Authors

Supaporn Pumriw Faculty of Agricultural Technology, Kalasin University, Kalasin, 46000 Thailand
Boonyote Kamjijam Faculty of Agricultural Technology, Kalasin University, Kalasin, 46000 Thailand
Jintana Sangsopha Faculty of Science and Technology, Phetchaburi Rajabhat University, Phetchaburi, 76000 Thailand
Thorung Pranil Creative Food and Tourism Research Unit, Faculty of Tourism and Hotel Management, Mahasarakham University, Maha Sarakham, 44000 Thailand

Keywords:

Edible flowers, Total phenolic contents, Total flavonoid contents, Antioxidant activity, Antimicrobial properties

Abstract

Edible flowers have been traditionally consumed for their nutritional, medicinal, and culinary benefits worldwide. This study investigates the bioactive composition, antioxidant potential, and antibacterial properties of five pink-purple edible flowers in Thailand: Antigonon leptopus Hook. & Arn., Plumeria obtusa L., Bougainvillea glabra Choisy, Ixora chinensis Lam., and Nelumbo nucifera Gaertn. The total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (DPPH assay) were analyzed, along with antibacterial activity against Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, and Escherichia coli using the agar disc diffusion method. The results revealed significant variations in TPC, TFC and antioxidant activity among the tested flowers. N. nucifera exhibited the highest TPC (135.75 mg GAE/g dry extract), TFC (14.74 µg QE/g dry extract), and antioxidant capacity (127.37 µg Vit C/g dry extract), whereas B. glabra had the lowest values (12.19 mg GAE/g, 5.71 µg QE/g, and 49.44 µg Vit C/g, respectively). A similar trend was observed in antibacterial activity, where N. nucifera exhibited the most effective inhibition against S. typhimurium, B. cereus, S. aureus, and E. coli (1.02–1.22 cm inhibition zones), while B. glabra demonstrated the weakest antibacterial activity (0.00 cm against E. coli). Pearson correlation analysis further confirmed strong positive correlations between TPC and antioxidant activity (r = 0.660, p < 0.01), as well as TFC and antibacterial activity against E. coli (r = 0.758, p < 0.01). These findings indicate that phenolics and flavonoids play a major role in radical scavenging and antimicrobial mechanisms. This study provides new insights into the bioactive potential of flower extracts, highlighting N. nucifera as a promising natural antioxidant and antimicrobial agent for potential applications in functional foods and preservatives. Future studies should focus on identifying key bioactive compounds and optimizing extraction methods to maximize their therapeutic benefits.

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