Two years later, Hanum et al. compared the effects of macadamia nut oil nanocream and conventional cream for treating cutaneous aging over a 4-week period. The macadamia nut oil nanocream, which contained macadamia nut oil 10%, tween 80, propylene glycol, cetyl alcohol, methylparaben, propylparaben, and distilled water, was compared with the conventional cream based on effects on moisture, evenness, pore size, melanin, and wrinkling. The macadamia nut oil was found to yield superior anti-aging activity along each parameter as compared with the conventional cream. The researchers concluded that the macadamia nut oil in nanocream can be an effective formulation for providing benefits in addressing cutaneous aging.5
Macadamia tetraphylla
Matthieu Sontag/Wikimedia Commons/CC-BY-SA
Macadamia nut oil has also been used in an anti-aging emulsion that was evaluated in a small study with 11 volunteers in 2008. Akhtar et al. prepared multiple emulsions of vitamin C and wheat protein using macadamia oil for its abundant supply of palmitoleic acid. Over 4 weeks, the emulsion was found to increase skin moisture without affecting other skin parameters, such as elasticity, erythema, melanin, pH, or sebum levels.6
Sapucaia (L. pisonis), an ornamental tree that is used for timber, produces edible, nutritious nuts that are rich in tocopherols, polyphenols, and fatty acids.7,8 In 2018, Demoliner et al. identified and characterized the phenolic substances present in sapucaia nut extract and its shell. Antioxidant activity conferred by the extract was attributed to the copious supply of catechin, epicatechin, and myricetin, as well as ellagic and ferulic acids, among the 14 phenolic constituents. The shell included 22 phenolic substances along with a significant level of condensed tannins and marked antioxidant function. The authors correlated the substantial activity imparted by the shell with its higher phenolic content, and suggested this robust source of natural antioxidants could be well suited to use in cosmetic products.9
Antifungal Activity
In 2015, Vieira et al. characterized 12 fractions enriched in peptides derived from L. pisonis seeds to determine inhibitory activity against Candida albicans. The fraction that exerted the strongest activity at 10 μg/mL, suppressing C. albicans growth by 38.5% and inducing a 69.3% loss of viability, was identified as similar to plant defensins and thus dubbed “L. pisonis defensin 1 (Lp-Def1).” The investigators concluded that Lp-Def1 acts on C. albicans by slightly elevating the induction of reactive oxygen species and causing a significant reduction in mitochondrial activity. They suggested that their findings support the use of plant defensins, particularly Lp-Def1, in the formulation of antifungal products, especially to address C. albicans.10
Pruritus
In 2012, Silva et al. studied the antipruritic impact of L. pisonis leaf extracts in mice and rats. Pretreatment with the various fractions of L. pisonis as well as constituent mixed triterpenes (ursolic and oleanolic acids) significantly blocked scratching behavior provoked by compound 48/80. The degranulation of rat peritoneal mast cells caused by compound 48/80 was also substantially decreased from pretreatment with the ethanol extract of L. pisonis, ether-L. pisonis fraction, and mixed triterpenes. The L. pisonis ether fraction suppressed edema induced by carrageenan administration and the ethanol extract displayed no toxicity up to an oral dose of 2g/kg. The investigators concluded that their results strongly support the antipruritic effects of L. pisonis leaves as well as the traditional use of the plant to treat pruritus.2