Primitive Archer
Main Discussion Area => Primitive Skills => Topic started by: DanaM on August 05, 2008, 09:14:13 am
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Can I harvest milkweed/dogbane now and let it dry indoors? Or does it have to dry naturally?
I haven't found any dogbane yet, but lots of common and swamp milkweed around.
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Dana, it works now, just messy and sticky. I think the fibers are stronger later in the year, but I've used the green stuff and it works. It's also harder to get the outer bark/chaff off when you cut it green.
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Yeah, what Hillbilly said! :)
Don't try making cordage out of it wet either. It dries and shrinks and is pretty much useless.
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Thanks guys, I was thinkin of letting some dry for awhile. I found what I think may be dogbane, it doesn't look quite like what I find on the internet,
it has very narrow opposite, lancelote leaves and has milky sap. guess I will harvested a few and see eh.
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Oh, and be careful fooling with green fresh dogbane-it's full of cardiac glycosides. There are a couple different species of dogbane, they all work for cordage. Google Indian hemp dogbane and spreading dogbane for pics.
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What do the "cardiac glycosides " do to ya Steve? ???
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Everything you always wanted to know about cardiac glycosides but were afraid to ask: ;D ;D ;D ;D In other words, don't make dogbane salad. :o
Cardiac Glycosides
Increasing the force of contraction of the heart (positive inotropic activity) is very important for most heart failure patients. There are several mechanisms by which this could be achieved. Cardiac steroids are perhaps the most useful and are being discussed here. Phosphodiesterase inhibitors, such as amrinone and milrinone, have also been explored and so are direct adenylate cyclase stimulants, such as forskolin. These drugs all act by affecting the availability of intracellular Ca+2 for myocardial contraction or increasing the sensitivity of myocardial contractile proteins.
The cardiac glycosides are an important class of naturally occurring drugs whose actions include both beneficial and toxic effects on the heart. Plants containing cardiac steroids have been used as poisons and heart drugs at least since 1500 B.C. Throughout history these plants or their extracts have been variously used as arrow poisons, emetics, diuretics, and heart tonics. Cardiac steroids are widely used in the modern treatment of congestive heart failure and for treatment of atrial fibrillation and flutter. Yet their toxicity remains a serious problem.
Structure
Cardiac glycosides are composed of two structural features : the sugar (glycoside) and the non-sugar (aglycone - steroid) moieties. (figure below)
(http://www.people.vcu.edu/~urdesai/car.ht1.gif)
The R group at the 17-position defines the class of cardiac glycoside. Two classes have been observed in Nature - the cardenolides and the bufadienolides (see figure below). The cardenolides have an unsaturated butyrolactone ring while the bufadienolides have an a-pyrone ring.
(http://www.people.vcu.edu/~urdesai/car.ht2.gif)
Nomenclature : The cardiac glycosides occur mainly in plants from which the names have been derived. Digitalis purpurea, Digitalis lanata, Strophanthus grtus, and Strophanthus kombe are the major sources of the cardiac glycosides. The term 'genin' at the end refers to only the aglycone portion (without the sugar). Thus the word digitoxin refers to a agent consisting of digitoxigenin (aglycone) and sugar moieties (three). The aglycone portion (figure below) of cardiac glycosides is more important than the glycone portion.
(http://www.people.vcu.edu/~urdesai/car.ht3.gif)
Click the following links to view the three dimensional structures of digitoxigenin, digoxigenin, gitoxigenin, strophanthidin and bufalin. Let us discuss some of the important characteristics of each structural feature.
The aglycone moiety: The steroid nucleus has a unique set of fused ring system that makes the aglycone moiety structurally distinct from the other more common steroid ring systems. Rings A/B and C/D are cis fused while rings B/C are trans fused. Such ring fusion give the aglycone nucleus of cardiac glycosides the characteristic 'U' shape as shown below. To view the 3-dimensional structure of the aglycone moiety click on the figure.
(http://www.people.vcu.edu/~urdesai/car.ht4.gif)
The steroid nucleus has hydroxyls at 3- and 14- positions of which the sugar attachment uses the 3-OH group. 14-OH is normally unsubstituted. Many genins have OH groups at 12- and 16- positions. These additional hydroxyl groups influence the partitioning of the cardiac glycosides into the aqueous media and greatly affect the duration of action.
The lactone moiety at C-17 position is an important structural feature. The size and degree of unsaturation varies with the source of the glycoside. Normally plant sources provide a 5-membered unsaturated lactone while animal sources give a 6-membered unsaturated lactone.
Sugar moiety : One to 4 sugars are found to be present in most cardiac glycosides attached to the 3b-OH group. The sugars most commonly used include L-rhamnose, D-glucose, D-digitoxose, D-digitalose, D-digginose, D-sarmentose, L-vallarose, and D-fructose. These sugars predominantly exist in the cardiac glycosides in the b-conformation. The presence of acetyl group on the sugar affects the lipophilic character and the kinetics of the entire glycoside. Because the order of sugars appears to have little to do with biological activity Nature has synthesized a repertoire of numerous cardiac glycosides with differing sugar skeleton but relatively few aglycone structures.
Structure - Activity Relationships
The sugar moiety appears to be important only for the partitioning and kinetics of action. (see section on pharmacokinetics of cardiac glycosides) It possesses no biological activity. For example, elimination of the aglycone moiety eliminates the activity of alleviating symptoms associated with cardiac failure.
The "backbone" U shape of the steroid nucleus appears to be very important. Structures with C/D trans fusion are inactive.
Conversion to A/B trans system leads to a marked drop in activity. Thus although not mandatory A/B cis fusion is important.
The 14b-OH groups is now believed to be dispensible. A skeleton without 14b-OH group but retaining the C/D cis ring fusion was found to retain activity.
Lactones alone, when not attached to the steroid skeleton, are not active. Thus the activity rests in the steroid skeleton.
The unsaturated 17-lactone plays an important role in receptor binding. Saturation of the lactone ring dramatically reduced the biological activity.
The lactone ring is not absolutely required. For example, using a,b-unsaturated nitrile (C=C-CN group) the lactone could be replaced with little or no loss in biological activity.
Pharmacokinetics of Cardiac Glycosides
The commercially available cardiac steroids differ markedly in their degree of absorption, half-life, and the time to maximal effect (see table below).
Agent GI absorption Onset (m) Peak (h) Half-life
Ouabain Unreliable 5-10 0.5-2 21 h
Deslanoside Unreliable 10-30 1-2 33 h
Digoxin 55-75% 15-30 1.5-5 36 h
Digitoxin 90-100% 25-120 4-12 4-6 days
Usually this is due to the polarity differences caused by the number of sugars at C-3 and the presence of additional hydroxyls on the cardenolide. Although two cardiac glycosides may differ by only one sugar residue their partition co-efficients may be significantly different resulting in different pharmacokinetics. For example, lanatoside C and digoxin differ only by a glucose residue and yet the partition co-efficient measured in CHCl3/16% aqueous MeOH are 16.2 and 81.5, respectively.
Glycoside Partition Coefficient
Lanatoside C (glucose-3-acetyldigitoxose-digitoxose2-digoxigenin) 16.2
Digoxin (digitoxose3-digoxigenin) 81.5
Digitoxin (digitoxose3-digitoxigenin) 96.5
Acetyldigoxin (3-acetyldigitoxose-digitoxose2-digoxigenin) 98.0
G-Strophanthin (rhamnose-ouabagein) very low
In general, cardiac glycosides with more lipophilic character are absorbed faster and exhibit longer duration of action as a result of slower urinary exretion rate. Lipophilicity is markely influenced by the number of sugar residues and the number of hydroxyl groups on the aglycone part of the glycoside. Comparison of digitoxin and digoxin structures reveals that they differ only by an extra OH group in digoxin at C-12, yet their partition coefficients differ by as much as 15 % points.
Biochemical Mechanism of Action
The mechanism whereby cardiac glycosides cause a positive inotropic effect and electrophysiologic changes is still not completely clear. Several mechanisms have been proposed, but the most widely accepted involves the ability of cardiac glycosides to inhibit the membrane bound Na+-K+-ATPase pump responsible for Na+-K+ exchange.
The process of muscle contraction can be pictured as shown below.
(http://www.people.vcu.edu/~urdesai/car.ht5.gif)
The process of membrane depolarization / repolarization is controlled by the movement of three cations, Na+, Ca+2, and K+, in and out of the cell. At the resting stage, the concentration of Na+ is high on the outside. On membrane depolarization sodium fluxes-in leading to an immediate elevation of the action potential. Elevated intracellular Na+ triggers the influx of free of Ca++ that occurs more slowly. The higher intracellular [Ca++] results in the efflux of K+. The reestablishment of the action potential occurs later by the reverse of the Na+-K+ exchange.
The Na+ / K+ exchange requires energy which is provided by an enzyme Na+-K+-ATPase. Cardiac glycosides are proposed to inhibit this enzyme with a net result of reduced sodium exchange with potassium that leaves increased intracellular Na+. This results in increased intracellular [Ca++]. Elevated intracellular calcium concentration triggers a series of intracellular biochemical events that ultimately result in an increase in the force of the myocardial contraction or a positive inotropic effect.
[session home] [home] [school of pharmacy] [department of medicinal chemistry]
©2000 VCU School of Pharmacy
Revised: January 5, 2000
Questions or Comments : Dr. Umesh R. Desai
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Whollywa eh!!! ???
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;D
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Whollywa eh!!! ???
Couldn't have said it any better myself Pat :D
So can you absorb it thru the skin or do you have to ingest it?
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just like hillbilly said. to remove the chaff from a green plant let it dry then use a knife or sharp rock, my favorite, and lightly scrape the chaff off before removing the fibers from the pith. you can also rett it but it takes time. the fibers are more than strong enough this time of year as the growing season is over and now its time for seed prduction. i made 6 dogbane strings in the last couple weeks. definetly work outdoors or with a fan blowing if the is no wind. all the chaff i scraped off created some serious dust and i started feeling like crap. the milkweed wont get ya sick like dogbane will but its still not cool to breathe in latex dust either.
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Thanks jamie, think I will wait another week or two, our milkweed is still blooming.
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If anyone comes across some ripe milkweed seed pods I'd be interested in some for wind indicators while hunting. ;) Pat
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Pat remind me in about a month and I will send ya some ok :)
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milkweed
you mean the plant with the big green stalks,large seed pods,kind of silky type seeds and white sticky milky sap?
if thats it, i know where thare are literaly hundreds growing, 3-4 ft tall atleast
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Thats it, you can make cordage from the stalks, seed pods =wind indicator, the flowers before they open are edible, kinda band but edible :)
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Holy cow Steve, I logged on and thought I hit the OSU extension site by mistake. All those molecules and stuff "scir'd" me.
After seeing the article in PA on Milk Weed Cordage, I've had my eye on a lot of milk weed lately.
Can't wait.
Mike
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can the cordage thats made from milkweed be used as bow strings?
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Tim it most certainly can :)
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if you use it as bow material you need to do a very good job of removing the chaff ( outer bark) . it creates a week spot and is nothing but dead weight if you leave it on. im going to put an article together for the mag on using plant fibers for strings. i really delved into it this month to figure out the easiest way to produce clean fibers quickly without having to rett it. retting is the best method but waiting 3-4 weeks for the outer bark to rot just isnt practical at times. peace
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Let's not forget the stuff is toxic. If retting you need to make sure your animals and kids stay out of it.
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Informative thread. :)
Zuma
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Is it toxic? The young pods are edible, people make fritters from the flowers, and apparently the young stalks are also quite edible. You can buy pickled milkweed pods from Forbes wild foods, and I've eaten quite a few of the pods myself.
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I think some of this is crossing over on itself. I don't think milkweed is really all that toxic but I may be wrong.
Dogbane or Indian hemp on the other hand is very poisonous. Cattleman hate it because it can make cows sick and even kill them. I gather my dogbane in the late fall when the stalk has hardened to a dark reddish hue. You will also notice it has thin black looking pods hanging from the limbs. They are like a super skinny green bean pods. I usually cut it at ground level and then cut it agin at the first branch. Around here that gives me about a 2 1/2 foot stalk. I use my knife to lightly scrape the surface bark or thin layer off. Then crush it along it's length getting several separate long pieces. You can the go from one end to the other breaking 2 inch pieces along its length and pilling the fibers away from the inner core. You can get great fibers the full length of the stalk in one piece.
Dogbane seems to be a fluffy soft cordage but very strong. Watch in fields for thin tall dark stalks and then look closer for the thin dangling pencil lead pods....Good luck
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Interesting link. Where is that from? The only issue I saw was 'figure A', or at least the first picture, talks about the steroid as an aglycan when there is a sugar bound to it, so it is glycosylated. Later on when they show the OH instead of the glycan it is appropriately an aglycan. End of the day though, the stuff is bad for you so be careful. Digitalis, one of the molecules listed in the linked information, I think was the poison the twins used in the episode of the X-Files called Eve. I don't know how accurate the show was, but they described it as being very sweet flavored so perhaps if you have worked with the material and taste anything on your fingers that is oddly sweet call poison control ASAP.
SOM