Multifactorial stress modulation of secondary metabolism in Theobroma cacao and Coffea arabica: from growth chamber to field and human bioavailability

Abstract

Theobroma cacao and Coffea arabica accumulate secondary metabolites (SMs) that determine crop resilience, beverage quality, and consumer health outcomes. A Box-Behnken response-surface design applied four simultaneous stress factors soil water status (30–70% field capacity), atmospheric CO? (400–800 µmol mol?¹), UV-B irradiance (0–4 kJ m?² d?¹), and foliar methyl jasmonate (0–200 µM) to seedlings of both species for 21 days. The optimal combination (55% field capacity, 600 µmol mol?¹ CO?, 2 kJ m?² d?¹ UV-B, 100 µM methyl jasmonate) raised total polyphenols by 38% in cacao (42.3 to 58.4 mg GAE g?¹ DW) and 44% in coffee (68.1 to 98.1 mg GAE g?¹ DW). Chlorogenic acid gains in coffee reached 52%; procyanidin gains in cacao, 31%. Methylxanthines were unaffected (<12% variation). Field validation at two Ecuadorian sites (250 m and 1,100 m a.s.l.) recovered 68–72% of laboratory increments. A 24-participant randomized cross-over pilot demonstrated significantly higher plasma Cmax (0.82 vs. 0.54 µM; P = 0.004) and AUC0–24 (8.4 vs. 5.7 µM·h; P = 0.009) for chlorogenic acid catabolites after stress-enhanced coffee versus control. These results provide a translational framework for agronomic protocols that enrich bioactive SM profiles in cacao and coffee.