Spyag (Wrinkled Leaf Isodon)

Isodon rugosus (Wrinkled Leaf Isodon)

Vernacular name: Spyag (in Kinnauri)

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Isodon rugosus (Lamiaceae), commonly known as Wrinkled Leaf Isodon or Spyag in Kinnauri, is a member of the mint family native to a wide geographical range, stretching from eastern Afghanistan through India and Nepal to Bangladesh. The genus Isodon includes over 100 species primarily distributed across tropical and subtropical Asia, with the Hengduan Mountains region in China recognized as the primary center of species diversity.

Fun facts:

The pollen of Isodon rugosus (Wrinkled Leaf Isodon) is a major food source for bees in spring, making it an important plant for honey production in the region. Both the Eastern honeybee (Apis cerana) and the European honeybee (Apis mellifera) forage on its flowers. Interestingly, A. cerana hives have shown an increase in brood rearing and honey yield—ranging from 4 to 12 kg per colony, depending on the location—after the flowering of I. rugosus. In contrast, A. mellifera colonies often show a decrease in brood rearing after Isodon blooms, though they may still produce surplus honey in particularly good seasons or favorable areas.

Another fascinating observation is that even when I. rugosus flowers are sparse and scattered, A. cerana can still locate and forage from them effectively—while A. mellifera struggles to do so. This suggests that native honeybees like A. cerana may be better adapted to utilizing local floral resources, such as Isodon rugosus, compared to the introduced A. mellifera.

Uses

In traditional medicine:

Isodon rugosus has been traditionally used to relieve various types of pain, including toothaches, gastric and abdominal discomfort, earaches, and general body aches. Recent phytochemical studies of its essential oil have identified several bioactive compounds—such as benzyl alcohol, sebacic acid, myristic acid, phytol, sugiol, tocopherol, α-amyrin, and stigmasterol—all of which are known for their analgesic (pain-relieving) properties. These findings offer scientific support for its long-standing use in traditional medicine.

As an insecticide:

• Scientific studies have shown that Isodon rugosus exhibits strong insecticidal activity against the pea aphid (Acyrthosiphon pisum). One of its key compounds, rosmarinic acid, has proven to be significantly lethal to pea aphids even at low concentrations, highlighting its potential for use in organic and eco-friendly farming practices.

• In Kinnaur, Spyag is traditionally used to repel insects. Locals cut its branches and place them in homes, between folded clothes, or in cow sheds—often in the form of a jhadu (broom)—to keep insects at bay. The plant’s strong aroma is believed to drive insects away, offering a natural and sustainable method of pest control.

References

1. Ullah, S., Zafar, M., Ptaszyńska, A. A., Ahmad, M., Ahmad, S., Ullah, A., ... & Islamov, S. (2025). Taxonomic implications of pollen morphological features for taxa identification: Plant–honeybee interactions. Genetic Resources and Crop Evolution, 72(2), 1835-1852. 

2. Khan, S., Taning, C. N. T., Bonneure, E., Mangelinckx, S., Smagghe, G., Ahmad, R., ... & Shah, M. M. (2019). Bioactivity-guided isolation of rosmarinic acid as the principal bioactive compound from the butanol extract of Isodon rugosus against the pea aphid, Acythrosiphon pisum. PLOS ONE, 14(6), e0215048.

3. Yu, X. Q., Maki, M., Drew, B. T., Paton, A. J., Li, H. W., Zhao, J. L., ... & Li, J. (2014). Phylogeny and historical biogeography of Isodon (Lamiaceae): Rapid radiation in south-west China and Miocene overland dispersal into Africa. Molecular Phylogenetics and Evolution, 77, 183-194. 

4. Shah, F. A., & Shah, T. A. (1989). Comparative foraging behaviour of Apis cerana Fabr. and Apis mellifera L. during Isodon rugosus (Wall.) Codd bloom in Kashmir Valley. Apidologie, 20(1), 85-91.