Skin color disorders can be caused by various factors, such as excessive exposure to sunlight, aging and hormonal imbalance during pregnancy, or taking some medications. Kojic acid (KA) is a natural metabolite produced by fungi that has the ability to inhibit tyrosinase activity in synthesis of melanin. The major applications of KA and its derivatives in medicine are based on their biocompatibility, antimicrobial and antiviral, antitumor, antidiabetic, anticancer, anti-speck, anti-parasitic, and pesticidal and insecticidal properties. In addition, KA and its derivatives are used as anti-oxidant, anti-proliferative, anti-inflammatory, radio protective and skin-lightening agent in skin creams, lotions, soaps, and dental care products. KA has the ability to act as a UV protector, suppressor of hyperpigmentation in human and restrainer of melanin formation, due to its tyrosinase inhibitory activity. Also, KA could be developed as a chemo sensitizer to enhance efficacy of commercial antifungal drugs or fungicides. In general, KA and its derivatives have wide applications in cosmetics and pharmaceutical industries.

In recent years, the researchers and drug designers have given growing attention to new nanotechnology strategies to improve drug delivery to the central nervous system (CNS). Nanotechnology has a great potential to affect the treatment of neurological disorders, mainly Alzheimer's disease, Parkinson's disease, brain tumors, and stroke. With regard to neurodegeneration, several studies showed that nanomaterials have been successfully used for the treatments of CNS disorders. In this regard, nanocarriers have facilitated the targeted delivery of chemotherapeutics resulting in the efficient inhibition of disease progression in malignant brain tumors. Therefore, the most efficacious application of nanomaterials is the use of these substances in the treatment of CNS disease that enhances the overall effect of drug and highlights the importance of nano-therapeutics. This study was conducted to review the evidence on the applications of nanotechnology in designing drug delivery systems with the ability to cross through the blood-brain barrier (BBB) in order to transfer the therapeutic agents to the CNS.

Glycyrrhiza glabra L. has been used in herbal medicine for skin eruptions, including dermatitis, eczema, pruritus and cysts. The effect of licorice extract as topical preparation was evaluated on atopic dermatitis. The plant was collected and extracted by percolation with suitable solvent. The extract was standardized, based on Glycyrrhizinic acid by using a titrimetry method. Different topical gels were formulated by using different co‐solvents. After standardizing of topical preparations, the best formulations (1% and 2%) were studied in a double–blind clinical trial in comparison with base gel on atopic dermatitis over two weeks (30 patients in each group). Propylene glycol was the best co‐solvent for the extract and Carbopol 940 as gelling agent showed the best results in final formulations. The quantity of glycyrrhizinic acid was determined 20.3% in the extract and 19.6% in the topical preparation. Two percent licorice topical gel was more effective than 1% in reducing the scores for erythema, oedema and itching over two weeks (p<0.05). The results showed that licorice extract could be considered as an effective agent for treatment of atopic dermatitis.