Arjuna, or Terminalia arjuna, is a large evergreen tree that grows abundantly throughout India. Different parts of the tree have been used traditionally for a wide variety of ailments,^[1][10][11] and the bark has often been used for cardiovascular concerns.^[12][11] Traditionally, an extract has been made from arjuna by heating powdered bark in alcohol, clarified butter, or milk.^[13][14]

Most of the randomized controlled trials examining arjuna have investigated its effects on cardiovascular health or heart function. Improvements in outcomes related to heart failure were found in 4 of 5 trials.^{[2][9][8][15][3]}

One trial found arjuna effective for skin moisturization in postmenopausal women, but conflicts of interest reduce our confidence in the results.^[16]

Arjuna contains various compounds such as flavonoids (60%–70%), tannins (20–24%), phytosterols, triterpenoids, and saponins and has shown blood-pressure-lowering, anti-inflammatory, antioxidant, anti-atherosclerotic, and cardiotonic (strengthening the heart) effects.^{[13][1][17][12][18][19][20][14]}

In studies in cats and dogs, arjuna reduced blood pressure in a dose-dependent manner, likely by activating adrenergic beta-2 receptors (which causes blood vessels to dilate), and/or by acting directly on heart muscle cells.^[21][22][14]

In rodent studies, arjuna has shown anti-inflammatory activity by inhibiting COX-2 enzymes and histamine and increasing antioxidant enzymes like glutathione S-transferase, superoxide dismutase, and catalase (which gets rid of hydrogen peroxide, a harmful byproduct of cellular metabolism).^{[23][24][25][26][27][12]} Arjuna also inhibited lipid peroxidation and prevented the associated decrease in the levels of antioxidants such as glutathione.^[28][18][19] In one study, arjuna decreased the size of atherosclerotic lesions (areas of plaque buildup), likely by decreasing cholesterol levels.^[29]

In in vitro studies, arjuna extract improved the contractility and relaxation of rodent heart cells by increasing calcium levels.^[30][13]