The increasing production of tropical fruits followed by their processing results in tons of waste, such as skins or seeds. However, these by-products have been reported to be rich in bioactive compounds (BACs) with excellent properties of interest in the cosmeceutical industry: antioxidant, anti-aging, anti-inflammatory, antimicrobial and photoprotective properties. This review summarizes the tropical fruits most produced worldwide, their bioactive composition and the most important and studied therapeutic properties that their by-products can contribute to skin health, as well as the different approaches for obtaining these compounds using techniques by conventional (Soxhlet, liquid-liquid extraction or maceration) and non-conventional extractions (supercritical fluid extraction (SFE), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE) and two-phase aqueous system), followed by their identification by HPLC-MS or GC-MS analysis. Moreover, this work encompasses several studies that may prove the effects of seeds and skins from tropical fruits against oxidative stress, hyperpigmentation, acne, aging or UV radiation. Therefore, the investigation of functional components present in tropical fruit by-products under a circular bioeconomy model could be of great interest for the cosmeceutical industry and a very promising option for obtaining new cosmeceutical formulations.

The constant growth of the cosmetic industry, together with the scientific evidence of the beneficial properties of phytochemicals, has generated great interest in the incorporation of bioactive extracts in cosmetic formulations. This study aims to evaluate the bioactive potential of a mango peel extract for its incorporation into cosmetic formulations. For this purpose, several assays were conducted: phytochemical characterization; total phenolic content (TPC) and antioxidant potential; free-radical scavenging capacity; and skin aging-related enzyme inhibition. In addition, the extract was incorporated into a gel formulation, and a preliminary stability study was conducted where the accelerated (temperature ramp, centrifugation, and heating/cooling cycles) and long-term (storage in light and dark for three months) stability of the mango peel formulations were evaluated. The characterization results showed the annotation of 71 compounds, gallotannins being the most representative group. In addition, the mango peel extract was shown to be effective against the ^•NO radical with an IC₅₀ of 7.5 mg/L and against the hyaluronidase and xanthine oxidase enzymes with IC₅₀ of 27 mg/L and 2 mg/L, respectively. The formulations incorporating the extract were stable during the stability study. The results demonstrate that mango peel extract can be a by-product to be revalorized as a promising cosmetic ingredient.

Annona cherimola fruit, known as cherimoya or custard apple, is an exotic fruit from South America but is strongly produced in Andalusia, Spain. Its by-products (seeds and peel) are recognised as important sources of antioxidants, including phenolic acids, flavonoids and procyanidins. Therefore, the aim of this study was to carry out the characterization of its phenolic composition and to in vitro evaluate the bioactivity of custard apple seed and peel. Therefore, high performance liquid chromatography coupled to mass spectrometry (HPLC-ESI-qTOF-MS) was performed in order to tentatively identify their phenolic composition. In the end, 19 compounds were identified and quantified, some of them for the first time in the custard apple matrix. Then, seed and peel total phenolic content, as well as antioxidant properties, radical scavenging capacity (O₂, NO, HOCl) and inhibition of enzymes involved in different pathologies (hyaluronidase, elastase, collagenase, tyrosinase, acetylcholinesterase and xanthine oxidase), were evaluated. Although both extracts showed almost similar antioxidant capacities, custard apple seed stood out slightly more than peel (171 ± 2 vs. 130.0 ± 0.4 μmol TE/g DE, resp.), especially as ·NO scavenger (IC₅₀ 1.5 ± 0.2 vs. 11.8 ± 0.3 mg/L, resp.) and hyaluronidase inhibitor (IC₅₀ 170 ± 10 vs. 460 ± 20mg/L, resp.). Finally, the application of extracts on a real human model of platelet aggregation was performed, reporting antiaggregatory effects in agonist-promoted platelet thrombus formation. All these results show that custard apple by-products are stated as interesting sources of bioactive compounds with multiple industrial applications for the development of high-added-value products, such as functional foods, nutraceuticals and cosmeceuticals, promoting the circular bioeconomy of these by-products.

Cherry stems, prized in traditional medicine for their potent antioxidant and anti-inflammatory properties, derive their efficacy from abundant polyphenols and anthocyanins. This makes them an ideal option for addressing skin aging and diseases. This study aimed to assess the antioxidant and anti-inflammatory effects of cherry stem extract for potential skincare use. To this end, the extract was first comprehensively characterized by HPLC-ESI-qTOF-MS. The extract’s total phenolic content (TPC), antioxidant capacity, radical scavenging efficiency, and its ability to inhibit enzymes related to skin aging were determined. A total of 146 compounds were annotated in the cherry stem extract. The extract effectively fought against NO^· and HOCl radicals with IC₅₀ values of 2.32 and 5.4 mg/L. Additionally, it inhibited HYALase, collagenase, and XOD enzymes with IC₅₀ values of 7.39, 111.92, and 10 mg/L, respectively. Based on the promising results that were obtained, the extract was subsequently gently integrated into a cosmetic gel at different concentrations and subjected to further stability evaluations. The accelerated stability was assessed through temperature ramping, heating-cooling cycles, and centrifugation, while the long-term stability was evaluated by storing the formulations under light and dark conditions for three months. The gel formulation enriched with cherry stem extract exhibited good stability and compatibility for topical application. Cherry stem extract may be a valuable ingredient for creating beneficial skincare cosmeceuticals.

Custard apple (Annona cherimola Mill.) is a tropical fruit source of bioactive compounds whose main producer worldwide is Andalusia, Spain. Because of its processing, the food industry generates large amounts of by-products, such as peels and seeds. These by-products are rich in phenolic compounds with high antioxidant, anti-inflammatory and anti-aging powers. The objective of this work is to evaluate, by different in vitro methods, the antioxidant and anti-inflammatory potential of cherimoya by-products rich in phenolic compounds for the development of cosmeceuticals. In addition, the major phenolic compounds present in the custard apple peel and seed samples were characterized by HPLC-ESI-QTOF-MS. The results showed that both the peel and seed of custard apple have a strong potential against oxidative stress and inflammation. Its phytochemical profile due to the presence of phenolic compounds (catechin, epicatechin, rutin, quinic acid, vanillic acid, etc.) makes both industrial by-products attractive bioactive ingredients for the manufacture of functional food and cosmeceuticals.

The avocado is one of the most produced and consumed tropical fruits worldwide, so more than 1.5 million tons of waste are generated per year, especially due to its main by-products: the seed and peel. In order to demonstrate whether these extracts are able to exert health benefits related to oxidative stress, a series of in vitro tests were conducted: an identification and quantification using HPLC, and an evaluation of the antioxidant capacity and ability to inhibit enzymatic overactivation. In the end, the avocado peel stood out as the more antioxidant extract, due to its higher phenolic content. However, both extracts can be considered as great options for developing new, high added-value products.