Identification and characterization of anthocyanins present in banana bract of Indian origin

Importance of the Topic

Banana bracts are an abundant agricultural byproduct that display a vibrant purple hue, indicating a rich content of anthocyanins. As natural colorants attract growing interest for food, cosmetic and pharmaceutical applications, identifying new, cost-effective sources is essential. Banana bract, traditionally consumed without adverse effects and produced in large volumes in India, represents a promising raw material for anthocyanin extraction and valorization.

Objectives and Study Overview

This study aimed to extract, identify and characterize anthocyanin compounds present in banana bract of Indian origin. The work combined optimized extraction and purification methods with advanced UHPLC-MS/MS techniques to profile the anthocyanin composition and assess the potential of banana bract as a natural dye source.

Methodology and Instrumentation

Extraction and Purification:

• Sample preparation: 50 g fresh banana bract ground and extracted with 0.15% HCl in methanol until colorless filtrate.
• SPE cleanup: C18 cartridge conditioned with methanol and acidified water, sample loaded, washed to remove polar interferents and eluted with acidified methanol.
• Final concentrate reconstituted in 1.5 mL 0.01% HCl in water.

Chromatography and Mass Spectrometry:

• LC system: UHPLC Nexera (Shimadzu) with Phenomenex Luna C18(2) column (50 mm × 3 mm, 2.5 µm).
• Mobile phase: A – 0.1% trifluoroacetic acid in water; B – methanol; gradient from 10% to 100% B over 15 min; flow rate 0.5 mL/min; oven at 40 °C; UV detection at 520 nm.
• Mass spectrometer: LCMS-8030 triple quadrupole with electrospray ionization; nebulizing gas 3 L/min, drying gas 15 L/min; DL 300 °C, heat block 400 °C.
• Acquisition modes: product ion scan, precursor ion scan, neutral loss scan targeting sugar moieties (162 Da hexose, 308 Da rutinose).

Key Results and Discussion

The extract yielded a series of molecular ions at m/z 449, 463, 465, 479, 493, 595, 609, 611, 625 and 639, corresponding to monohexoside and rutinoside derivatives of five anthocyanidins: cyanidin, peonidin, delphinidin, petunidin and malvidin. Retention times ranged from 3.16 to 4.88 min, enabling rapid profiling without extensive chromatographic separation. Fragmentation patterns confirmed sugar losses of 162.2 Da and 308.2 Da, validating the glycosylation patterns. The combination of scan modes provided comprehensive structural information and selective detection of anthocyanins in a complex plant matrix.

Benefits and Practical Applications

Use of banana bract anthocyanins offers:

• Economic valorization of agricultural waste into high-value natural colorants.
• Potential replacements for synthetic dyes in food and cosmetics.
• Rapid, sensitive analytical workflow suitable for quality control and standardization.

Future Trends and Potential Applications

Advancements could include scaling extraction processes, exploring additional glycosylation patterns, and integrating high-resolution mass spectrometry for deeper profiling. Further studies may optimize formulation stability, bioavailability and color performance in diverse product matrices. Biotechnological approaches might enhance anthocyanin yield in banana cultivars or engineer novel derivatives.

Conclusion

This work demonstrates that banana bract from Indian sources contains a diverse array of glycosylated anthocyanins and can serve as an economical and sustainable natural dye. The implemented UHPLC-MS/MS strategy offers a robust platform for rapid anthocyanin identification and quality assessment, supporting future commercial applications.

References

• [1] E. Alexandra Pazmiño-Durán et al., Anthocyanins from banana bracts (Musa X paradisiaca) as potential food colorants, Food Chemistry, 73(3), 327–332 (2001).
• [2] M. Monica Giusti, L. E. Rodríguez-Saona et al., Electrospray and Tandem Mass Spectroscopy as Tools for Anthocyanin Characterization, J. Agric. Food Chem., 47, 4657–4664 (1999).
• [3] M. C. Lazzé, R. Pizzala et al., Anthocyanins protect against DNA damage induced by tert-butyl-hydroperoxide in rat smooth muscle and hepatoma cells, Mutat. Res. Genet. Toxicol. Environ. Mutagen., 535(1), 103–115 (2003).