From Threat to Opportunity: Harnessing the Invasive Carpobrotus edulis (L.) N.E.Br for Nutritional and Phytotherapeutic Valorization Amid Seasonal and Spatial Variability

Carpobrotus edulis (L.) N.E.Br. (Hottentot-fig) is a problematic invasive species found in coastal areas worldwide. Mechanical removal is a common control method, leaving the removed biomass available as a possible source of natural phytochemicals with prospective commercial applications. While the Hottentot-fig’s vegetative organs have been studied previously, this work establishes for the first time a seasonal and spatial comparative analysis of its nutritional, chemical, and bioactivity profiles (in three locations over four seasons). Proximate and mineral contents were assessed, along with its phenolic composition and in vitro antioxidant and anti-inflammatory properties. Hottentot-fig’s biomass offered a good supply of nutrients, mainly carbohydrates, proteins, and minerals, with a tendency for higher concentrations of the most relevant minerals and proteins in autumn and winter, and in plants from sites A (Ria de Alvor lagoon) and B (Ancão beach). The extracts were rich in polyphenolics, with higher levels in spring and summer, especially for luteolin-7-O-glucoside and salicylic and coumaric acids. The extracts were also effective antioxidants, with stronger radical scavenging activities in spring and summer, along with anti-inflammatory properties. Our results suggest that the usually discarded plant material of this invasive halophyte could be valuable as a source of natural products with potential biotechnological applications in the food and nutraceutical industries.