Hydrogels are polymeric materials that possess a set of characteristics meeting various requirements of an ideal wound dressing, making them promising for wound care. These features include, among others, the ability to absorb and retain large amounts of water and the capacity to closely mimic native structures, such as the extracellular matrix, facilitating various cellular processes like proliferation and differentiation. The polymers used in hydrogel formulations exhibit a broad spectrum of properties, allowing them to be classified into two main categories: natural polymers like collagen and chitosan, and synthetic polymers such as polyurethane and polyethylene glycol. This review offers a comprehensive overview and critical analysis of the key polymers that can constitute hydrogels, beginning with a brief contextualization of the polymers. It delves into their function, origin, and chemical structure, highlighting key sources of extraction and obtaining. Additionally, this review encompasses the main intrinsic properties of these polymers and their roles in the wound healing process, accompanied, whenever available, by explanations of the underlying mechanisms of action. It also addresses limitations and describes some studies on the effectiveness of isolated polymers in promoting skin regeneration and wound healing. Subsequently, we briefly discuss some application strategies of hydrogels derived from their intrinsic potential to promote the wound healing process. This can be achieved due to their role in the stimulation of angiogenesis, for example, or through the incorporation of substances like growth factors or drugs, such as antimicrobials, imparting new properties to the hydrogels. In addition to substance incorporation, the potential of hydrogels is also related to their ability to serve as a three-dimensional matrix for cell culture, whether it involves loading cells into the hydrogel or recruiting cells to the wound site, where they proliferate on the scaffold to form new tissue. The latter strategy presupposes the incorporation of biosensors into the hydrogel for real-time monitoring of wound conditions, such as temperature and pH. Future prospects are then ultimately addressed. As far as we are aware, this manuscript represents the first comprehensive approach that brings together and critically analyzes fundamental aspects of both natural and synthetic polymers constituting hydrogels in the context of cutaneous wound healing. It will serve as a foundational point for future studies, aiming to contribute to the development of an effective and environmentally friendly dressing for wounds.

Bakuchiol is a meroterpene that has recently aroused great interest in the cosmetic and pharmaceutical industries. Its main source is the seeds of Psoralea corylifolia, a medicinal plant native to Asia, despite having a wide geographical distribution. However, this medicinal herb faces endangerment due to low seed germination rates and high seedling mortality. In this context, this review article highlights studies that have focused on describing plant regeneration from root fragments. Subsequently, given its morphological similarity to other species, a technique that can be used to verify the authenticity of the plant and prevent counterfeiting is also mentioned and explored. Additionally, a “green” extraction method for obtaining bakuchiol is presented, and the possibility of obtaining bakuchiol through chemical synthesis routes is also explored. Furthermore, we provide an exhaustive description of bakuchiol's wide range of biological activities, with particular relevance to the skin. The main skin bioactivities of bakuchiol include antifungal, antibacterial, antioxidant, anti-inflammatory, antiaging, depigmenting, and anticancer. However, the particular physicochemical properties of bakuchiol require and benefit from the development of innovative skin delivery systems that allow its encapsulation. These include micro- and nano-sized systems for therapeutic and cosmetic applications, which are also carefully described in this review article. Finally, regulatory issues, metabolic considerations, and toxicological concerns related to the use of bakuchiol in cosmetic and dermopharmaceutical formulations will be addressed, relating not only to the user but also to the environment. Graphical abstract