Monday, July 29, 2013

Let's Eat Tearthumb!

Since Kew Gardens has based this year's summer festival on edible plants, aptly named IncrEDIBLES, and because I love edible botany, I've been thinking some more about which plants we could eat. Although most of the time ecologists want to protect plants and increase biodiversity, there is one particular time when most ecologists will agree, the plants must be destroyed, eradicated, extirpated from an area. I know this sounds harsh, but I'm talking about invasive exotic species. These are pest species which have come from other habitats, often other countries, and they love their new habitat so much that they out-compete local native plants. Such invasive species can eliminate local endemic species, reduce the number of once common plants, disrupt the ecosystem and all the ecosystem services that it once provided, and be a real headache for habitat managers and gardeners alike.

Today, I came across a new book that has just been published in my home area of Maryland called A Quick Guide to Wild Edible Plants: Easy to Pick, Easy to Prepare. One of the wild edibles mentioned in the book is tearthumb or mile-a-minute weed (Polygonum perfoliatum), a nasty invasive plant that plagues our home in Maryland by climbing over plants, smothering my mother's wonderful garden, and becoming larger and more problematic every year. So I am delighted to find out that it's berries are edible!!

According to the US Forest Service, Mile-a-Minute weed is edible by humans and has a high potassium content. Does this mean we could skip imported tropical bananas and eat seeds from the garden instead!? And, based on the following excerpt from a journal article written about Mile-a-Minute weed, it is not only edible, but it is also use in Asia as an herbal medicine and could even be used as an anticancer agent! I wonder, if we started eating the seeds if it would cause even a small dent in the speed this invasive is taking over?
In its native eastern Asia, mile-a-minute is considered beneficial and has been used as an herbal medicine for over 300 yr (He et al. 1984; Hoque et al. 1989; Sook and Myung 1992; Yang and Kim 1993; Zhu 1989), or as an edible wild fruit (Bajracharya 1980). The plant also serves as a suitable food source for a diverse group of mammals, birds, and insects. Two protein kinase C inhibitors (PKC), vanicosides A and B; five diferuloyl esters of sucrose; and feruloylsucroses have been isolated from mile-a-minute plants (Sun 1999; Sun et al. 2000). PKC are involved in cell signal transduction and cell proliferation and are believed to be tumor promoters; thus PKC inhibitors could be used as potential anticancer agents (Sun 1999). Two well-known natural products, quercetin and beta-sitosterol, have also been isolated from mile-a-minute (Sun 1999). Beta-sitosterol is also reported to have anticarcinogenic properties (Park et al. 2003). The bioflavonoid quercetin has antioxidant (Boadi et al. 2003; Kumar et al. 2003; Pietruck et al. 2003), antiproliferative, and anti-inflammatory properties (Pietruck et al. 2003).
Kumar, V., & Ditommaso, A . (2005). Mile-a-Minute (Polygonum perfoliatum): an increasingly problematic invasive species. Weed Technology 19(4), 1071-1077.


Anonymous said...

I think eating the seeds to reduce the spread of the plant is a very good idea. Do you have specifics on ripeness and how to eat the seeds?


karsten m.o. said...

Eating the seeds is a cool idea-but a terrible in the scope of a management plan. From the perspective of someone who wants to control this weed in their yard, you should be out hand pulling or raking plants as soon as you see them come up. Seed is the only method of propagation for these guys. You'd have to get every single berry off the bush, even the green ones because they have also been shown to have a decent germination rate. so, as far as eating the seeds goes. It's a nice sentiment but not really possible under a diligent, effective management plan because you wouldn't be allowing them to seed in the first place.