Herbal Glossary : Fructus Psoraleae

Original plant of Fructus Psoraleae Dried Fruits Name Latin Name: Fructus Psoraleae
Common Name: Malaytea Scurfpea Fruit, Psoralea
Scientific Name: Psoralea corylifolia L.
Chinese Name: 補骨脂
Pinyin Name: Bu gu zhi Origin The ripe fruit of Psoralea corylifolia L., an annual herb of Leguminosa. Where Does It Grow? Mainly produced in Henan, Sichuan and Shanxi provinces of China. Nature and Taste It is pungent and bitter in taste, warm in nature and manifests its therapeutic actions in the kidney and spleen meridians. Identified Active Components/ Major Chemical Constituents Fructus Psoraleae includes volatile oil, coumarin, flavones, monoterpene phenols, lipid compounds, resins and stigmasteroids.

Volatile oils include limonene, terpin-4-ol, linalool, β -caryophyllene and geranyl acetate.

Coumarin derivatives include psoralen, isopsoralen, psoralidin, isopsoralidin, corylidin, bavacoumestan A, bavacoumestan, B sophoracoumestan A and 8-methoxypsoralen.

Flavones include coryfolin, corylifolinin, bavachinin, isobavachin, neobavaisoflavne, bavachromene, corylin, bavachalcone and neobavachalcone.

Mono-terpane-phenol includes bakuchiol.

Lipids include triglycerides, diglycerides and monoglycerides.

Others include free fatty acids, stigmasterol, daucosterol, triacontane, glucose and saponin.
Historical Use The Chinese name of Buguzhi (Fructus Psoraleae) is actually comprised of three Chinese words. The first word "Bu" (補) means "to invigorate". The second word "Gu" (骨) means "bone", and the third word "Zhi" (脂) means "fat". The Chinese name of the herb suggests the function of the herb is to provide fat (rich materials) for invigorating the bones. In TCM, bones are ruled by the kidneys. Therefore, the herb was regarded by the ancient herbalists as being a good and rich source for invigorating the kidneys. Buguzhi is also known as Poguzhi. This name comes from the translation as voyagers from other countries first brought this herb to China.

During the Ming Dynasty, Li Shizhen wrote in the Bencao Gangmu (Compendium of Materia Medica):"Poguzhi (Fructus Psoralea) belongs to fire, it can gather together the spirit (shen) by allowing the fire of the vital gate (healthy fire inside the kidneys) to communicate smoothly without obstruction with the fire of the pericardium (healthy fire inside the heart). This results in the primordial yang being held firm and solid and keeps the bone marrow (supplemented by kidney essence) full and rich."

The Bencao Congxin (New Compilation of Materia Medica) describes Fructus Psoraleae as having pungent and bitter tastes with highly warm properties which enter the pericardium and vital gate (kidney) meridians. It invigorates the prime-minister fire (healthy fire inside the kidneys) and connects with the monarch fire (healthy fire inside the heart). It warms dan tian, strengthens primordial yang and reduces excessive urination. Historically, Fructus Psoraleae has been used to treat gasping and coughing caused by deficiency type cold, soreness and pain in the lower back and knee joints, disorders of seminal discharge or diarrhea caused by a deficiency of kidney fire (kidney yang) and for spontaneous abortions caused by blood and qi disorders in women.
What is It Used for in TCM? Fructus Psoraleae invigorates the kidneys and strengthens yang, consolidates essence (jing) and reduces excessive urination, warms the spleen and relieves diarrhea, supports the grasping of qi and relieves deficiency type gasping.
1. Treatment of cold pain symptoms in the lower back and knees, impotence, urinary frequency caused by kidney yang deficiency or deficiency of fire in the vital gate (healthy fire inside the kidneys). 2. Treatment of diarrhea caused by spleen and kidney yang deficiency:
Fructus Psoraleae can invigorate kidney yang to warm the spleen thereby relieving diarrhea. Although the kidneys belong to the water element, kidney yang is regarded as the healthy fire inside the water and belongs to the fire element. Healthy fire is essential in keeping the water warm without it getting too cold. Harmony between water and fire is an important concept for kidney health. The fire element can produce earth according to the five elements theory. Therefore, the spleen being an earth organ is supported by kidney yang and in turn relieves diarrhea. 3. Treatment of deficiency type gasp caused by a kidney deficiency.
One of the functions of the kidneys is to grasp qi (vital energy). The kidneys enable the "natural air qi" of the lungs to penetrate deeply during the inhalation process. If kidney yang is deficient, the resulting inability of the kidneys to grasp qi may lead to shallow breathing and in turn give rise to gasping. 4. Treatment of vitiligo. Pharmacological Actions 1. Effect on Cardiovascular System
Animal studies Corylifolinin, an identified active ingredient of Fructus Psoraleae was shown to increase coronary blood flow in isolated guinea pig hearts. Psoralen derivatives were also reported to increase blood volume in coronary arteries and peripheral blood vessels of dogs. 2. Anti-cancer Effect
Animal studies Direct anti-tumor effects were measured by adding 0.1ml Fructus Psoraleae solution to 0.9ml of different tumor cell suspensions. They were then each inoculated subcutaneously into the right axilla (armpit) of mice. Afterwards, Fructus Psoraleae was injected intraperitoneally(i.p.) at a dose of 0.05mg/kg once daily for ten days. The in-vitro results showed that inhibitory rates on S180, EAC or H22 tumor cells were 100%, 100% and 98% respectively.

In another study mice inoculated with S180, EAC or H22 cells were given Fructus Psoraleae intraperitoneal(i.p.) injection at a dose of 0.5mg/kg, once daily for ten days. The inhibitory rates for S180, EAC or H22 tumors were 40.2%, 68.0% and 20.5%, respectively.
In-vitro studies Application of 1.25mg psoralen (an active ingredient of Fructus Psoraleae) to sarcoma (S180) cells cultured at 2x107 cells/ml at 37°C for ninety minutes showed 100% cell death rates.

In another separate study, 0.1ml of S180, mouse Ehrlich ascites carcinoma cells (EAC) and mouse liver cancer cell (H22) cultures (2x107 cells/ml) were cultured with 5μg of psoralen respectively. The percentage proportion of radioactivity of 1 mL supernatant fluid among the total radioactivity incorporated into the cancer cells was then calculated. Results showed that psoralen treatment could increase the radioactivity release rate on S180, EAC and H22 cells. 3. Estrogen-like Effects
Animal studies When ovariectomized female mice were fed with 0.35 or 0.175g Fructus Psoraleae seed powder everyday, reversible vaginal keratinization was noted to occur. It appeared that Fructus Psoraleae possessed some very weak estrogen-like effects and such effects were not attributable to the active ingredient psoralen. When immature female mice were fed with 0.25g Fructus Psoraleae, their vagina opened prematurely. In another study where mature female mice were fed with 0.35g Fructus Psoraleae seed powder for 37 to 77 seven days, their reproductive ability was impaired. One week following resumption of normal diet, their reproductive ability resumed. In contrast, when male mice were fed with Fructus Psoraleae for 46 days, no abnormality was observed. 4. Effects on white blood cells
Clinical observations When 19 leucopenia patients were treated with three to nine pills of Fructus Psoraleae honey pills (9mg per pill), 14 patients showed complete recovery, four patients showed improvement while one patient experienced no change.

Human subjects orally administered with 2mg/kg and 1mg/kg Fructus Psoraleae, followed by fifty minutes of light illumination, showed a decreased lymphocyte transformation rate.
Animal study Subcutaneous injection of a 75% ethanol extract of Fructus Psoraleae (twice a day for three days) to cyclophosphamide immuno-suppressed mice was able to restore decreased white cell numbers and to promote the growth of granulocytes.12-13 5. Effects on skin conditions
Clinical observations An ethanol extract of 30% Fructus Psoraleae was applied topically to 36 cases of verruca vulgaris several times a day. The effective rate was reported to be 94.4% with the remaining 5.56% of cases showing improvement. The effective treatment rate of verruca plana was reported to be 85% with 15% of cases showing improvement.

In another study, an i.m. injection of 4ml/day of Fructus Psoraleae for ten days reported an effective treatment rate of 93% for psoriasis. The mean time for cure and/or alleviation of symptoms was 33.5 days. A separate study showed a combination of orally administered 8-methoxypsoralen (0.5mg/kg), an active ingredient of Fructus Psoraleae, followed by light illumination resulted in an effective treatment rate of 97.8% for psoriasis vulgaris.

When 0.2ml of Fructus Psoraleae was directly injected into 163 cases of people with corns, the successful treatment rate after one single injection was reported to be 84%.
Cell-culture study Fructus Psoraleae ethanol extracts (5, 10, 15 and 20mg) and tyrosinase (1200u/ml) were mixed together and put into a 37°C water bath for five minutes. Results showed that Fructus Psoraleae could increase tyrosinase activity. It is thought that Fructus Psoraleae exerts its therapeutic effects on vitiligo, by increasing the rate of synthesis and amount of melanin, and hence encouraging skin to recover from a vitiliginous state. 6. Toxicity
Acute toxicity: When mice were treated by gavage with organic extracts of Fructus Psoraleae, bakuchiol (an active ingredient of Fructus Psoraleae) and psoralen, the LD50 was found to be 38.0±3.5g (raw herb), 2.3±0.18ml/kg and 180±29.6mg/kg, respectively for each extract.
Sub-acute toxicity: This was investigated in rats by feeding the animals with a 100mg/kg corylifolinin (an active ingredient of Fructus Psoraleae) preparation by gavage for one month. No significant effects on blood pressure, ECG, hemogram, liver function and blood glucose were detected.

When mice were administered by gavage 0.125, 0.25, 0.5, and 1.0mg/kg bakuchiol (an active ingredient of Fructus Psoraleae) for one to four weeks, pathological changes in the kidneys were observed. In the high dosage groups, pathological changes appeared to be progressive. No abnormality was found in other major organs.

Mice administered by gavage 50, 100, 200mg/kg of Isopsoralen for three days showed no pathological changes in the heart, liver, spleen, lungs and kidneys. Dogs administered with 10-100mg/kg Isopsoralen for ten to fourteen days showed no alteration in liver and kidney functions, ECG readings or major pathological organs damage. Administration and Dosage A decoction is typically made with 6-15g of Fructus Psoraleae and three to four cups of boiling water until the volume is reduced by half. A decoction is usually taken orally and split into two doses but this dose may taken all at once or escalated depending on the person's condition and recommendation by the Chinese medicine practitioner. Adverse Effect, Side Effects and Cautions Fructus Psoraleae is contraindicated in individuals with heat caused by yin deficiency and in individuals with constipation.