Cosmetic degradation: A study on body lotions with botanical extracts

Abstract

Lipid oxidation is a spontaneous process in fats and, consequently, in products with significant fat content. Many cosmetics fall into this category, presenting an intrinsic relationship between the productʼs quality, oxidation capacity, and market value. This study comprehensively investigated the aging of body lotions, accentuating the role of their chemical formulations. Sensory analysis clarified that controlled temperature-induced aging significantly altered the lotions' appearance, texture, color, and, to a lesser extent, odor, hinting at the onset of rancidity. As lipid peroxidation unfolds, the emergence of secondary oxidation products like aldehydes, ketones, and alcohols becomes prominent. These secondary products indicate a potential degradation in the lotion's quality and efficacy. Quantifying the primary oxidation products was possible using methods like the quantification of Conjugated Dienes (CD) expressed in percentage and the Peroxide Index (PI) method expressed in meqO2/kg of a dry sample. On the other hand, methods such as the p-Anidisine Index (pAi) and the thiobarbituric acid reactive substances (TBARS) with malonaldehyde (MDA) expressed as malonaldehyde concentration (mg/g of dry sample) provided the quantification of secondary oxidation products. Regarding lipid oxidation, lotions containing sunflower and soybean oils emerged as notably susceptible. Conversely, samples that demonstrated minimal oxidation, were attributed to protective elements such as Aloe barbadensis and Calendula officinalis extracts. Examining into secondary oxidation, four samples displayed the highest TOTOX values, indicating extensive oxidation. A discernible correlation was observed between TOTOX values and natural extracts' presence (or lack), underscoring their protective or exacerbating roles. Certain natural ingredients, including A. barbadensis leaf juice powder and C. officinalis flower extract, were recognized as supporters against oxidation. Yet, components like PEG-40 hydrogenated castor oil can, paradoxically, seem to intensify the oxidative cascade. This research provides crucial insights into the interplay between natural extracts and lipid oxidation in body lotions. The elucidated results accentuate the necessity for judicious ingredient selection, balancing the inclusion of natural extracts to ensure product quality, longevity, and safety.