In traditional Chinese medicine, Gynostemma pentaphyllum (Thunb.) Makino is a herbal drug of extreme versatility and has been extensively researched in China. The dammarane saponins isolated from Gynostemma pentaphyllum, namely gypenosides or gynosaponins, are believed to be the active components responsible for its various biological activities and reported clinical effects.

This review attempts to encompass the available literature on Gynostemma pentaphyllum, from its cultivation to the isolation of its chemical entities and a summary of its diverse pharmacological properties attributed to its gypenoside content. Other aspects such as toxicology and pharmacokinetics are also discussed. In vitro and in vivo evidence suggests that Gynostemma pentaphyllum may complement the popular herbal medicine, Panax ginseng, as it also contains a high ginsenoside content and exhibits similar biological activities.

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Therefore, G. pentaphyllum has since been included in the most recent dictionary of Chinese Materia Medica, where the plant is prescribed in TCM for heat clearing, detoxification, antitussive, heart palpitation, fatigue syndrome, chronic bronchitis and expectorant for relieving cough (Wu, 1998; Blumert and Liu, 1999). In Japan, it is indicated as a diuretic, antipyretic, anti-inflammatory and tonic (Lin et al., 1993; Chen et al., 1996; Tanner et al., 1999).

Valentina Razmovski-Naumovski, Tom Hsun-Wei Huang, Van Hoan Tran, George Qian Li, Colin C. Duke, Basil D. Roufogalis: Chemistry and Pharmacology of Gynostemma pentaphyllum. In: Phytochemistry Reviews. 4, No. 2-3, July 2005, p. 197–219, doi:10.1007/s11101-005-3754-4.

The methods and optimal conditions for growing G. pentaphyllum are outlined in China Pharmaceutical University (1996), Wang et al. (1996) and Guo and Wang (1993). A soil (pH in the range 5.5–8.0, with an optimal pH of 6.5–7.0) more than 30 cm deep, rich in humus, nitrogen, phosphorus and moisture, is ideal for growing G. pentaphyllum. The optimal soil is well aerated and retains water, such as a fertile sandy loam.

G. pentaphyllum prefers to grow in a warm and humid environment. The viable air temperature is -15–41.5 C. The optimal air temperature is 15–30 C. The light factor is important for growing G. pentaphyllum (Huang et al., 2004). The plant prefers shady areas, with a viable relative illumination of 40–80% and optimal relative illumination of 65–75%. Under these conditions, the output is the highest, the blossoming and bearing of fruit is increased and the total saponin content is the highest (Guo and Wang, 1993; Wang et al., 1996).

Wind damage is common for this vine plant and can be reduced by introducing wooden sticks so that the plant can intertwine itself. An ideal chemical fertiliser is a nitrogen–phosphate–potassium compound (2–3 times) during the active growth period. Pests such as ants and snails can be controlled by various commercially available products. G. pentaphyllum may be collected when the vine reaches 2–3 m in length.

A recent report also cited that the total gypenoside content
in sweet Gp was about 34% more than in the bitter one (Zheng,
2004). These results suggest that sweet tasting Gp plants have a
more complex and rich gypenoside profile.

What about cold? I've read its only hardy to USDA zone 8?

Valentina Razmovski-Naumovski et al: Chemistry and Pharmacology of Gynostemma pentaphyllum:

The viable air temperature is -15–41.5°C . The optimal air temperature is 15–30°C .

The toxicity of one cucurbitacin is enhanced by the introduction of a double bond at carbon C23, of an acetyl group at C25, or a double bond at carbons C1-C2.

Do you recommend brewing a tea from bitter leaves?