Distribution and Importance of the Plant
Pinellia ternata Breit (Chinese name Banhsia), a perennial grass belonging to the Araceae, is an important Chinese medicinal herb that has been used in clinical practice for over 2000 years. Tuber globulose about 1 cm in diameter with hairy roots, few leaves with small bulbils of 3-5 mm in diameter borne at the middle and on the uppermost part; petioles 15-20 cm long, leaflets 3, ovate -elliptic to oblong – elliptic, 3-10 cm long, 1-3 cm broad, accuminate to acute at apex, acute to obtuse at base. Peduncles 25-35 cm long, spathe 6-7 cm long, green or green white rounded at apex, the limb lanceolate, puberulent inside; Spadix – erect, 6-10 cm long, with a filiform exerted appendage. It is widely distributed in China, especially in the south province, except for Nei Mongolia, Xin Jiang, Qing Hai, and Tibet. The altitude of these areas is below 2500 m. Pinellia ternata is one of the weeds in nonirrigated farm land (dry land), commonly seen in grassland, uncultivated land, corn fields, and/or under sparse woods. The species is also distributed in Japan and the Korean Peninsular. The plant grows well in warmer and more humid places and withstands damp or less sunshine. It is usually cultivated under woods or among fruit trees, or intercropped with other crops.
The Chinese traditional medicine Banhsia (Pinellia ternata Breit) is processed from the ball-like stem tuber of the plant, which is 1-2 cm in diameter. The earliest records of its use in clinical practice were more than 2000 years ago, and many prescriptions containing Pinellia ternata are still found today, e.g., Banhsia Shu Mi Tang and Banhsia Hou Pu Tang in Jin Kui Yao Lue (a famous treatise by Jing Zhong Zhang), the principle of which is P. ternata, are still adopted in China and Japan. According to the statistical results, in 558 Chinese precriptions, in frequency of appearance of P. ternata has the 22 place, and in 210 Japanese statutory precriptions, 46 contain P. ternata, with a frequency of 22%. P. ternata has the function of easing coughing, reducing phlegm, and preventing vomiting. It can be used together with other herbal drugs for analgesic and sedative effects, and has special efficacy for coughs, full and bloated feeling in stomach, nausea, and vomiting. It is also used to cure acute mastitis, acute or chronic suppurative otitis, etc..
Conventional Practice for Propagation
There are three traditional methods for propagation of Pinellia teranta ()
1. Propagation Through Seeds. Plants over 2 years old bloom successively from May to July, and fruits ripen in August. Take out the ripened seeds and cover with slightly moist sand, sow in the coming spring. The plants propagated through seeds grow slowly, usually taking 3 years to harvest tubers, and the quality (represented by tuber size) varies greatly.
2. Propagation Through Bulbils. There are bulbils at the base of leaves or in/ above the leaf sheath 3-5 mm in diameter, germinating at the plant or after excision from the plant into soil. The number of bubils is limited and cannot meet the demand of cultivation in large areas.
3. Propagation Through Small Tubers. This is the most common method for traditional propogation of P. ternata; 2-3 years after sowing, the tubers grow to 7-10 cm in diameter; these larger tubers begin to germinate to form small tubers. This method, however, demands large numbers of small tubers, usually taking 1/3-1/4 of the tuber production. Moreover, the tuber production and medicinal components decrease with long-term propagation of the plant through small tubers.
The in vitro culture technique of Pinellia ternata has been well developed. Because this plant has a strong ability for regeneration, workers could obtain plantlets under different kinds and concentrations of hormone combinations. Up to now, plantlets have been regenerated via the culture of stem tips, leaf spades, petioles, tubers, immature fruits, and stems. Plantlets were obtained from the cultured explants directly, as well as regenerated from callus. Viable protoplasts isolated from leaf spades, callus and cell suspension developed into calli and subsequent plantlets. We obtained calli in the culture of stem tips and established cell suspension cultures. A great number of viable single cells were selected from the suspension cultured cell aggregates. These cells could develop into calli and plantlets, and consequently field-grown plants.
The regeneration of plantlets of Pinellia ternata from in vitro cultures was once considered to be via the production of adventitious buds, tubercules, or embryoids. By observation under the stereomicroscope and the serial sections, we demonstrated that the plantlets were formed by way of the “tubercule”, which was characterized by typical terminal bud development.
The period of plantlets directly developed from the petiole was 45 to 50 days, while that of plantlets regenerated from callus was 50 to 60 days. More than 90% of the soil-transplanted plantlets regenerated from both calli and directly from explants have survived.
The tuber yield of the plants derived from in vitro cultures was much higher than that from cultivars and the most noticeable was that the total alkaloid production of cultured callus was 2.38 times higher than that of cultivated tubers.
The limitation of low rate of propagation in the traditional method of cultivating Pinellia ternata resulted in constraint of the cultivated acreage and high production cost when tubers were used. The in vitro culture technique can provide a reliable resource for field-growing. Theoretically, a petiole explant of 0.5 cm long can be propagated into 6561 plantlets in a year, the fine characters of the original strains can be kept, the plants will grow evenly, and the yield of qualified tubers will be high. We have obtained satisfactory results from the test zone. It is possible to use this technique in field planting.
Some important components were found in the tubers of the plants, e.g., β-sitosterol, β-sitosteryl-D-glucoside, homogentisic acid, β-aminobutyric acid, glutamic acid, arginine, aspartic acid, plamic acid, and some kinds of alkaloids (though no details have been reported about their structure, except for ephedrine). The total content of alkaloids in tubers derived from in vitro-cultured plants was 69.5%, and 30.0% higher than that from cultivated and wild-grown plants, respectively. Furthermore, the alkaloid content in calli derived from wild and cultivated plants was 89.8 and 137.9% higher than that of their control, respectively (tubers derived from wild and cultivated plants). Thin layer chromatography showed that the nature of some main alkaloid components in calli or cells was the same as in tubers.
Selections from the book: Medicinal and Aromatic Plants VIII (1995).