d-Pinitol: a cyclitol with versatile biological and pharmacological activities

d-Pinitol (3-O-methyl-d-chiro-inositol) is a cyclitol nearly ubiquitous in the Leguminosae and Pinaceae families. It plays an important role in plants as physiological cellular modulator and chemical defense against unfavorable environmental conditions, such as water deficit and high level of salinity. Plants rich in d-pinitol are being used in traditional medicine as empirical treatment for diabetes, inflammation, cancer or infections. This review summarizes the extensive literature published about d-pinitol biosynthesis, plant distribution, biological activities and pharmacological studies, including in vitro, in vivo, and clinical trials.