# Bioprospecting the Rodriguan Lime (Citrus aurantifolia Swingle) as a Novel Source of Antioxidants and Antimicrobials for Food Application

## TL;DR

The Rodriguan lime is explored as a new source of antioxidants and antimicrobials for food use, showing promising properties.

## Contribution

The Rodriguan lime is identified as a novel citrus source with unique phytochemicals and antimicrobial potential.

## Key findings

- Rodriguan lime extract showed the lowest MIC against several bacteria.
- Rodriguan grapefruit had the highest total phenolic and flavonoid content.
- LC-MS data revealed unique flavonoid and coumarin profiles in Rodriguan lime.

## Abstract

In view of bioprospecting the Rodriguan lime (Citrus aurantifolia Swingle) as a novel antioxidant and antimicrobial for the food industry, its bioactivities were compared with those of the Mauritian pamplemousses (Citrus maxima) and the Rodriguan grapefruit (Citrus × paradisi Macfad). The Rodriguan lime, “Limon Rodrigues,” is also known as the Mexican lime (Citrus aurantiifolia, Swingle) or key lime. All citrus peel extracts tested in the study—namely, the Rodriguan lime, Mauritian pamplemousses, and Rodriguan grapefruit—exhibited comparable antioxidant activity in the ferric reducing antioxidant power (FRAP) (14.50 ± 3.11, 12.96 ± 0.97, and 14.77 ± 1.47) and CUPRAC (cupric reducing antioxidant capacity) (0.71 ± 0.20, 0.50 ± 0.04, and 0.59 ± 0.11) assays. The Rodriguan lime extract had the lowest overall minimum inhibitory concentration (MIC) of 5–10 mg/mL against Staphylococcus aureus, Salmonella enterica, Listeria monocytogenes, Bacillus cereus, and Lactobacillus plantarum. Although the Rodriguan grapefruit peel had the highest total phenolic content (64.53 ± 3.25 mg GAE/g extract) (p < 0.05), its total flavonoid content was not significantly different from that of the Rodriguan lime peel (p > 0.05). LC-MS data revealed that the Rodriguan grapefruit extract possessed the highest overall concentration of flavonoids (4821.1 mg RE/kg) and coumarins (13476 mg CE/kg), although the Rodriguan lime peel extract exhibited a relatively unique flavonoid and coumarin profile. Citrus flavonoids and coumarins exhibit diverse biological functions, including antidiabetic, antimicrobial, antifungal, hypotensive, antioxidant, carminative, antibacterial, larvicidal, antiviral, uricosuric, antiyeast, antihepatotoxic, and antimutagenic activities. Additionally, they demonstrate significant anticancer, cardiovascular-protective, and neuroprotective properties. These multifunctional bioactive compounds highlight the potential of citrus-derived substances in therapeutic and preventive health applications. Given its broad antimicrobial spectrum and diverse phytochemicals, the Rodriguan lime extract shows potential for applications in the functional food and nutraceutical industries.