Sustainable methods for flavonoid determination: Applications with modern green analytical techniques

Flavonoids are a diverse group of polyphenolic compounds. They are ubiquitously found in fruits, vegetables, tea, and medicinal plants. They play a pivotal role in both plant physiology and human health. Numerous studies have demonstrated that these compounds exhibit a wide range of biological activities, including antioxidant, anti-inflammatory, cardioprotective, neuroprotective, and anticancer properties. Accordingly, significant research attention has been directed toward these compounds in nutraceutical, pharmaceutical, and food science research. Evidence is growing that a diet rich in flavonoids can help to prevent and manage several chronic diseases, including cardiovascular disorders, diabetes, neurodegenerative diseases, and certain cancers. However, the accurate quantification and characterisation of flavonoids remain a scientific challenge. This is due to their structural diversity, low stability, and matrix complexity in natural samples. Conventional analytical approaches, while widely used for their effectiveness, raise environmental concerns due to their reliance on toxic solvents and the resulting hazardous waste, which runs counter to sustainable chemistry principles. The escalating ecological and regulatory demands underscore the imperative to promptly implement green analytical methodologies that are both analytically robust and ecologically compatible. The present review focuses on studies published within the past five years. In recent years, modern green analytical techniques have reshaped approaches to phytochemical analysis by prioritizing sustainability alongside analytical performance. Examples of these techniques include supercritical fluid chromatography (SFC), microextraction techniques, capillary electrophoresis, and miniaturised spectrometric systems. These methods follow the principles of Green Analytical Chemistry (GAC) by using fewer reagents, reducing analysis time, and consuming less energy. Also, the use of combined methods (e.g., LC-MS/MS, GC–MS, or HPLC-DAD) with microfluidic systems and biosensors has created new possibilities for fast, portable measurement of flavonoids. This review provides a comprehensive examination of recent advances in green analytical techniques, emphasizing their methodological innovations and practical applications. By critically evaluating these developments, the work contributes to the ongoing transformation of natural product analysis, fostering approaches that are not only more sustainable but also resource-efficient and aligned with contemporary environmental imperatives. Moreover, it underscores the pivotal role of green analytical methodologies in improving analytical performance while minimising ecological impact.