Background  Taxus cuspidata S. et Z. is a precious species of frigid zone plant belonging to the Taxaceae family, which possesses anticancer, anti-inflammatory, hypoglycemic, and antibacterial pharmacological properties. While taxane extracted from Taxus chinensis has been reported to elicit antioxidant activities, whether Taxus cuspidata S. et Z. has skin-protective actions against injuries remained unknown. This study aims to explore the pharmacological effects of three Taxus extracts on skin melanin deposition, oxidation, inflammation, and allergy so as to provide new ideas for the prevention and treatment of various diseases related to skin damage.  Methods  Skin melanin deposition was evaluated by measuring melanin content in the skin of guinea pigs by alkali lysis method. Antioxidant capacity was evaluated by measuring superoxide dismutase (SOD) concentration and glutathione (GSH) content in skin tissue homogenates of Kunming mice by SOD assay kit and micro reduced GSH assay kit. The quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to examine the levels of both SOD and recombinant glutathione peroxidase 4 (GPX4). Skin inflammation was evaluated by xylene-induced ear swelling test and egg-white-induced paw swelling test in mice. In a mouse model of skin allergy induced by 4-aminopyridine (4-AP), allergy was determined by licking body counts and histamine concentrations in tissue homogenates using enzyme-linked immunosorbent assay (ELISA) kits. Two proinflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-1β were measured by qRT-PCR. Hematoxylin and eosin (HE) staining was conducted to assess the degree of skin lesion.  Results  All three Taxus extracts including Taxus chinensis essential oil, Taxus chinensis extract and Taxus chinensis extract compound reduced the melanin deposits in the back skin relative to the non-treated control animals, of which Taxus chinensis essential oil produced the greatest effect. In contrast, the three Taxus extracts elevated SOD and GSH levels in the skin tissues, and the highest increase was seen with Taxus chinensis essential oil. Three Taxus extracts, especially Taxus chinensis essential oil, effectively reduce the rate of ear and paw swelling. All three Taxus extracts reduced the number of body licks, the levels of TNF-α and IL-1β, and the histamine content in tissue homogenates of mice and alleviated skin damage. Consistently, Taxus chinensis essential oil yielded the greatest magnitude of decreases.  Conclusion  While all three Taxus extracts possessed the anti-skin melanin deposition, oxidation, and allergy properties, Taxus chinensis essential oil produced the superior effects.

Cold exposure increases the risk of adverse events related to cardiovascular causes, especially in the elderly. In this review, we focus on recent findings concerning the impact of aging on the regulatory mechanisms of cold-induced cardiovascular responses. In response to cold exposure, the initial physiological thermoregulation in healthy young persons, such as cutaneous vasoconstriction to reduce heat loss, is attenuated in older individuals, resulting in a reduced ability of the older persons to maintain body temperature in cold environment. Impaired sympathetic skin response, reduced noradrenergic neurotransmitter synthesis, insufficient noradrenergic transmitters, and altered downstream signaling pathways inside the vascular smooth muscle may be among the underlying mechanisms for the maladaptive vasoconstrictive response to cold stress in the elderly. The increase in blood pressure during cold exposure in young persons may be further augmented in aging adults, due to greater central arterial stiffness or diminished baroreflex sensitivity with aging. Cold stress raises myocardial oxygen demand caused by increased afterload in both young and old adults. The elderly cannot adjust to meet the increased oxygen demand due to reduced left ventricular compliance and coronary blood flow with advancing age, rendering the elderly more susceptible to hypothermiainduced cardiovascular complications from cold-related diseases. These age-associated thermoregulatory impairments may further worsen patients' health risk with existing cardiovascular diseases such as hypertension, coronary artery disease, and heart failure. We searched PubMed for papers related to cold stress and its relationship with aging, and selected the most relevant publications for discussion.