Zahra Mirzaei
Saffron (Crocus sativus L.) is a sterile triploid plant cultivated mainly in Iran, India, and Spain, recognized as the most expensive spice worldwide due to its unique apocarotenoid metabolites [1,2]. The biochemical basis of saffron quality resides in the flower, particularly the stigmas, which accumulate crocin, picrocrocin, and safranal—compounds responsible for its color, taste, and aroma [3–5]. These metabolites are synthesized through complex enzymatic pathways involving carotenoid cleavage dioxygenases (CCD2, CCD4) and UDP-glucosyltransferases (UGTs), which regulate apocarotenoid biosynthesis and stability [6–9]. Beyond secondary metabolism, saffron flowers rely on antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidases (POD) to mitigate oxidative stress during development and environmental fluctuations [10–12]. Hormonal regulation further integrates enzymatic activity, with gibberellin (GA), abscisic acid (ABA), and cytokinin (CK) pathways orchestrating flowering, stigma differentiation, and metabolite accumulation [13–15]. Recent advances in transcriptomics, proteomics, and metabolomics have provided insights into enzyme regulation in saffron, yet significant gaps remain in genomic resources [16–18]. Emerging approaches such as machine learning and CRISPR-based metabolic engineering offer promising strategies to enhance crocin yield and unravel enzyme functions [19–21]. This review critically examines the biochemical roles of enzymes in saffron flower development, highlighting their regulatory mechanisms, biotechnological applications, and future research directions.